Until the late ’90s, Carl Kasell was known among public radio listeners as the diligent reader of hourly news updates during NPR’s Morning Edition.

He was about to become celebrated for doing something completely different.

On January 3, 1998, Kasell opened the inaugural broadcast of Wait Wait … Don’t Tell Me, the weekly news quiz show that celebrated its 20th anniversary Wednesday. The show takes listeners on a lighthearted jaunt through a selection of the week’s news via several recurring games that rely heavily on the repartee of the host, scorekeeper, and a rotating panel of writers, comedians, and guests, ranging from Tom Hanks to Method Man.

Today, the show is a bona fide hit. According to NPR’s audience insights and research team, more than 4 million people listen to Wait Wait each week on the radio. Plus, according to analysis by Podtrac, the podcast of the show was the 10th-most-downloaded of 2017.

Quiz shows are having a moment, as the buzzed-about HQ Trivia continues to dominate conversation while Jeopardy! still produces its share of viral moments. But while it may be fun to hear HQ host Scott Rogowsky refer to himself as Quiz Khalifa or to watch Alex Trebek joust with a feisty contestant, the actual trivia in those competitions remains the main draw.

On Wait Wait, trivia is only the starting point. In the show’s opening game, the scorekeeper recounts three recent quotes from newsworthy figures, often parroting their cadences and affectations. The caller must identify whom the scorekeeper is impersonating in each quote. Each listener response is followed by a short monologue from host Peter Sagal contextualizing the quote and in-the-moment reactions from the three panelists. For instance, on a recent show, a quote from a newly declassified government video that was part of the secret Pentagon program to track extraterrestrial life leads to a joke insinuating that former Senate majority leader Harry Reid is an alien, which leads to a discussion of the possible benefits of an alien abduction. “Given what’s going on,” said Sagal, “the best chance I’ve got for health care is, like, an anal probe.”

It’s this spontaneity that makes Wait Wait feel more like a topical improv comedy show than Jeopardy!, though it contains elements of both. As with topical improv, Wait Wait is best enjoyed by listeners who have been paying attention to the news it satirizes. And as with Jeopardy!, the show has a game-show format that’s easy to follow. This hybrid identity allows the show to place the news in a digestible context. It also makes it unlike anything else NPR had ever produced.

That uniqueness is probably why Wait Wait struggled to gain an audience in its early years. Initial reviews of the show from its 191,300 weekly listeners across 32 stations were universally negative. “Stations were very upset that NPR was pushing [Wait Wait],” Sagal recalls. “‘Why are you doing this dumb show rather than X or Y or Z thing which we think you should be doing?’”

As the show attempted to convince public radio program directors that it was worth listening to, it was the reputation of the serious news guy that was integral to keeping Wait Wait on the air. “Carl’s presence on the show brought us both credibility and time,” says Sagal. “When people heard Carl’s voice, they said, ‘Well, this can’t be awful, because Carl’s doing it.’”

Wait Wait eventually found its way. After almost 16 years as the show’s announcer and scorekeeper, Kasell stepped down from his post in 2014 (he’s now the scorekeeper emeritus and still records voicemail greetings for winning listeners who request it) and was replaced by the extremely capable Chicago newscaster Bill Kurtis. Over the past two decades, Wait Wait has also changed hosts, executive producers, venues, and a long list of rotating celebrity panelists. What hasn’t changed is the show’s format. It was through the long process of fine-tuning this format in its early days that Wait Wait found its voice.

In the ’70s and ’80s, NPR barely provided enough programming to fill member stations’ weekday schedules with shows like Morning Edition, Fresh Air, and All Things Considered. NPR later acquired a few weekend shows, like American Public Radio’s A Prairie Home Companion, for stations to use whenever they saw fit. But for the most part, Saturday mornings had never been a particularly big listening time for public radio.

That is, until Car Talk.

“Car Talk was kind of a surprise hit for NPR,” says Doug Berman, who was the executive producer of the classic call-in show for its entire run. After the show’s premiere in Boston in 1987, it quickly began to be picked up at NPR member stations across the country. “Suddenly, Saturday morning was this huge hour of the week,” Berman says. “So a few years later, I guess the powers that be at NPR decided that they’d like to have something to go with it.”

“I thought the idea of it being a reward for people who listen to NPR all week would make sense. We would use what NPR does for the rest of the week as material for a show.” —Wait Wait... Don’t Tell Me creator Doug Berman

Tom and Ray’s small garage show, in which the charismatic brothers gave advice on how to fix cars while cracking jokes at callers and each other, became NPR’s first comedic hit. As a result, Berman earned a great deal of cachet in the public radio community. He was approached by Murray Horwitz, then the director of cultural programming for NPR, to create a new show to air after Car Talk.

Horwitz’s pitch for Berman was to reboot College Bowl, a broadcast quiz show that pitted teams of college students against each other — but to make it funnier. Berman was not enthusiastic about the suggestion. “I said, ‘That’s a terrible idea, Murray,’” Berman recalls. “‘Let me think about it.’”

It was after this conversation that Berman came up with the concept that became Wait Wait … Don’t Tell Me, a comedy quiz show to be centered on the main topic consumed by NPR listeners: the news. “I thought the idea of it being a reward for people who listen to NPR all week would make sense,” he says. “We would use what NPR does for the rest of the week as material for a show.”

Horwitz was thrilled with the idea and gave Berman his blessing. Berman partnered with WBEZ in Chicago and brought on Car Talk producer David Greene to pilot the new show.

The first of three practice shows was recorded in Washington, D.C., in 1996, featuring a cast of NPR news contributors, including Martha Raddatz, then covering the Pentagon, and Ray Suarez, who hosted a talk show on NPR before taking a role at PBS. “It was much too serious,” Berman says. “It just didn’t have enough humor in it.”

Berman stumbled upon an unexpected solution while at a meeting of public radio program directors in 1997. After a panel discussion with various NPR on-air personalities, an audience member asked the moderator, one Carl Kasell of Morning Edition, what time he woke up that morning.

“I set my alarm clock for 1:05,” Kasell replied.

Why 1:05? Why not 1:00?

“Oh, that’s just too early!”

“I kept that in my head,” Berman says. “‘Oh, Carl has a very funny deadpan and has got perfect timing.’” Berman invited Kassel to join the Wait Wait team for the remainder of the piloting process. Kasell, who was good friends with Horwitz and grew up loving radio variety programs, heartily agreed.

The second attempt was somewhat of an overcorrection from the previous one. This time, the show moved to New York and the host and panelists were mostly humorists and TV writers, including Randy Cohen and Steve O’Donnell. “That was funnier but almost too frivolous. There wasn’t enough substance in it,” Berman says. “We were looking for this middle ground.”

The third unaired pilot was the charm. It was hosted by Dan Coffey from Chicago, who came to NPR having previously hosted a daily radio sketch segment called Ask Dr. Science. The other panelists were plugged in remotely: Sagal checked in from a recording studio in New York, where he was living as a playwright; Roxanne Roberts called from NPR headquarters in Washington, D.C., where she worked as a Style reporter for The Washington Post; and Charlie Pierce joined from Boston, where he worked as a writer-at-large for Esquire. This mixed group of humorists and journalists struck the balance that the Wait Wait team wanted. The show was ready, they thought, to seek an audience.

When Wait Wait debuted in January 1998, it was as one of two new weekend shows from NPR. The other, called Anthem, was a pop culture variety show that Horwitz says struggled to be picked up by public radio program directors after its launch.

Though its circumstances were not as dire, Wait Wait had a rocky start. The first few months of episodes employed the arrangement of the final pilot episode: Coffey hosted from the WBEZ studios with the producers. Kasell acted as the scorekeeper from NPR headquarters in D.C. And the cast of panelists called in from studios in their home cities.

According to many of the people involved at the time, that arrangement was not working. “It’s been 20 years, and I was part of them, so I can say this. [Those early shows] were not very good,” Sagal says. “I can certainly tell you, without editorializing, that the reaction of the public radio community was not positive. I thought it had its moments, but as I remember saying to my wife at the time, I don’t think I’d listen to this show if I weren’t on it.”

The show’s initial reach was small; it wasn’t even broadcast in several major metropolitan areas, including New York. Panelist Adam Felber, a comedian and writer for Real Time With Bill Maher who first appeared on Wait Wait in March 1998, could not even convince his friends that it existed. “They referred to it as ‘Adam’s imaginary sideshow,’” Felber says.

“I think NPR was worried about it, especially in the first few months,” says Berman, who was then Wait Wait’s executive producer. “Fortunately for us, Anthem struggled so much that most of the attention was put on saving Anthem. We were allowed to figure out how to fix our show.”

Even though Wait Wait hadn’t yet been embraced by audiences, many of the early panelists enjoyed the show and its often silly games. “The show was a little bit disjointed at times, but it was a lot of fun,” Felber says. Roberts agrees. “I’ve always had a really good time doing the show,” she says.

With that internal feedback, the production team started to feel confident that the basic format of the show worked. But they were not convinced that they had found the right host.

“They were never really delighted by my hosting,” Coffey recalls via email. “And as the show jelled around me, they were even more disappointed. It became obvious that I was not a ‘news junkie’ with the gift of gab they wanted.” Berman confirms this assessment. “Dan is a really funny guy. He just wasn’t as into news as we needed. The conversation was going around him a little bit, and we needed someone who could stay in the middle of it.”

“Peter Sagal has a really hard job. But he does it so brilliantly well that it looks easy.” —Paula Poundstone

The Wait Wait producers decided to offer the job to Sagal, who had appeared as a panelist on all but two of the 17 Wait Wait episodes that aired before he took over as host in May 1998. The call came at an opportune time for Sagal and his now-ex-wife, since they were both looking to leave New York and the unpredictability of writing plays and movies. “It was not a hard decision for us. I really needed the stability,” Sagal says.

Though he was disappointed at the time, Coffey acknowledges now that the producers made the right call. “I could tell [the show] wasn’t working as well as they hoped and that was tough. Glad they had the good sense to promote Peter Sagal from panel member to host,” he says.

Twenty years later and it’s hard to imagine the show without Sagal at the helm. Not only does he possess the clear and relentless interest in current affairs that the show requires (just look at his Twitter feed for proof), he’s also able to effortlessly riff with any of the panelists who join him onstage. “Peter Sagal has a really hard job,” says Paula Poundstone, who joined the show in February 2001. “But he does it so brilliantly well that it looks easy.” Says Alonzo Bodden, who joined the show in October 2010: “Peter is like the glue.”

With Sagal as the host, the show started to grow, slowly. The formula took time to develop, but it was around this point that the Wait Wait team began to settle on specific segments that remain a part of the show today. For example, “Not My Job,” the now-weekly game where the host quizzes a celebrity guest about a topic they would know nothing about, made its debut during Sagal’s first show. During a recent episode, Method Man successfully answered questions about the Method acting techniques employed by Shia LaBeouf. In the show’s hardest game, called “Bluff the Listener,” which first appeared in September 1998, each panelist reads a story from the news related to a particular theme, but only one is true. It’s up to the listener to determine who is trying to deceive them.

Wait Wait was soon picked up by more stations, and its rotating cast of panelists expanded. But it became clear after a couple of years that the conditions that initially made that panel possible now prevented the show from growing any further. In order to corral and edit these voices from all over the country for cheap, the producers relied on existing ISDN technology, a hard-wired connection that allows producers to instantaneously transmit high-quality voice recordings to producers in other studios. The arrangement was often awkward.

“It was very hard to know if a joke landed,” recalls Mo Rocca, who first appeared on the panel in 2002. “You were only relying on the laughter of your copanelists, which is not the most reliable gauge. In the studio, it felt underwater. It felt remote,” he says.

Executive producer Mike Danforth, who joined as a producer in November 2000 and took over executive duties from Berman in the summer of 2008, concurs. “It was like the worst party you’ve been to, where everyone’s congratulating each other on their jokes.” To take its next step forward, Wait Wait needed to go all the way live.

Moving Wait Wait out of the studio and in front of an audience immediately improved its quality. In January 2000, the show’s producers were invited to record an episode in Salt Lake City, Utah. “It was just so great,” Berman says. “It was literally as if we had been rehearsing for years. As soon as we went in front of an audience, it was a hit. It solved all kinds of problems.”

From then on, even though the show was primarily recorded in the studio, Wait Wait started appearing in front of live audiences throughout the country many times a year. “There was such energy when you did it in front of a live audience,” Danforth says. “And the panelists really feed off that too. That really worked in the show’s favor.”

It became clear after a few years that the show was at its best in a live setting, so the production team started looking for a permanent venue in Chicago. In the spring of 2004, Wait Wait did a successful series of test shows in the Chase Bank Auditorium. The following year, that 500-seat space in downtown Chicago became the permanent home of Wait Wait … Don’t Tell Me.

“At first, people didn’t know to come to the show, so we had to give out free tickets,” Danforth says. “I remember emailing people at Second City and saying, ‘Hey we have this show, can you let all your improv kids know?’” More than 12 years later, tickets to the show usually sell out far in advance of the tapings.

“It was like the worst party you’ve been to, where everyone’s congratulating each other on their jokes.” —Mike Danforth, executive producer of Wait Wait, on the show’s early days

Since the move to the Chase Bank Auditorium, the creation of a Wait Wait … Don’t Tell Me episode doesn’t appear to have fundamentally changed. The show is recorded on Thursday nights over about two hours and then edited down to the 50-minute episode that airs during the weekend. Each new episode contains the same basic elements and games that one would have heard in 2005. What changes with each show are the topics discussed within. Who is in office doing what? What is the next big trend in food? How did scientists conduct the latest weird study? Week to week, the show is built off of all that the news has to offer it.

The producers and writers are picky about which topics they discuss, in order to cultivate the fun feel of the show. The show was envisioned to help people digest the news, to make light of all that happened in the week as a reward for paying attention. As such, Wait Wait has largely avoided stories that are too dark, like those about natural disasters or acts of terrorism.

The show has, however, joked about politics since it premiered in 1998, right at the beginning of the Monica Lewinsky scandal and Bill Clinton’s impeachment proceedings. Throughout the presidencies of George W. Bush and Barack Obama, Wait Wait and its panelists have effectively satirized and poked fun at all of the hypocritical positions, odd habits, and eclectic personas of politicians. In 2005, then-senator Obama appeared on the show to rail against eighth-grade graduation ceremonies.

The candidacy and presidency of Donald Trump has presented a challenge for Wait Wait, as it has for most topical comedy shows. But the show has taken painstaking action to keep jabs directed at the president from dominating the show. “Before some shows, Peter or a producer have asked the panelists to limit our Trump jokes to the first segments,” says Faith Salie, who first appeared on the show in October 2009. “We do the heavily charged stuff at the top of the show and get it out of the way,” says Tom Bodett, who joined the show in August 2005.

“I think what we always have to struggle with is how to be funny around stuff that has the potential to make people angry,” Berman says. “I think we have to walk very carefully to do it while making sure we make fun of people that deserve to be made fun of. The goal is the laugh, not the applause.”

As the show looks to its future, the producers and current panelists believe the basic format will remain the same. “The structure allows for the content and the commentary and the comedy to change along with the world,” says Berman, who now holds the title of Wait Wait’s “benevolent overlord.” “We [use] this quiz format to talk to interesting and funny people about what’s going on this week. And so what has changed over time are the different voices and perspectives that we bring in.”

When Wait Wait premiered, it featured a relatively small cast of regular panelists, including Roberts, Felber, Pierce, humorist Margo Kaufman, and Amy Dickinson. Once the show installed Sagal as the host and began to iron out the kinks of its format, the team quickly realized that in order for the show to keep growing, its panel also needed to grow. “The simplest way to evolve the show,” Danforth says, “is to just bring new people in.”

In the past this presented a challenge. Not only did the Wait Wait producers not have the money or the profile to attract all of the performers it wanted, but the show also struggled to find ones who could succeed within the format. “Wait Wait is a really hard show to do for performers,” Berman says. “It’s not easy to find people who are good at it. People who can be funny in a different setting are not funny or not sharp enough on Wait Wait. It’s a very small subset of people who can do it well.”

“Back in the day, finding a panelist who knew how to do the show was really difficult. We would try out people and it wouldn’t really work. That would happen a lot,” Felber says.

“As soon as we went in front of an audience, it was a hit. It solved all kinds of problems.” —Doug Berman

Now that Wait Wait is a well-known property, the search for willing and able talent is less challenging. “The biggest single thing we can do to keep the show fresh is adding more and better people to the panel,” says Sagal. The show has made a particularly aggressive effort in the past year to liven up proceedings: in 2017, nine comedians and writers made their debuts on the Wait Wait panel, the most since the show’s inaugural year. Some, like Patton Oswalt, are one-off guests, while several others, including Negin Farsad, have already become regulars. But the roster of regular panelists remains fairly small, currently hovering around 16 performers.

For those in this exclusive group, a Wait Wait gig is an important and profoundly enjoyable professional experience. “Being on Wait Wait is both fun and easy. Creative work is not often both,” says Rocca. “It’s kind of a dream.”

It’s also a badge of honor. When Tom Bodett, a longtime pioneer of public radio, was offered the opportunity to join Wait Wait as a panelist in August 2005, he was “floored.” “That show, the one that you genuinely like, never calls,” he says. “I’ve been around in the media world for over 30 years. To be associated with Wait Wait and NPR is a great source of pride for me.”

For Sagal, going on 20 years as Wait Wait host, that feeling has never diminished. “I should have noted the date and time [Berman asked me to audition for Wait Wait] in my diary. It turned out to be quite the phone call.”

How much longer will he go on? Sagal likens being the host of a hit public radio show to being the pope. “It’s a very hard job to get,” he says. “But once you get it, the only way to lose it is to die.”

He continues: “I certainly don’t want to outstay my ability to do a really good show. If I ever start getting stale and not providing actual pleasure to the audience, then I will be the first one who will agree that it’ll be time for me to go. I will find my own way to the door.”

If and when that time comes, Wait Wait has built a structure that can withstand Sagal’s departure. As long as the format endures, the show will always be worth waiting for.

Daniel Varghese is a writer for Wirecutter, the product-review site owned by The New York Times. He lives in Brooklyn, New York.

An earlier version of this story misstated when NPR news producer Rod Abid started working on Wait Wait. It was around 2000, not at the start of the show’s run. Also, the piece misstated the location of the show’s first live episode; it was in Salt Lake City, Utah, not Park City. Additionally, the piece misstated the year that Car Talk debuted; it was 1989, not 1987.