Though it didn’t make much of a dent in the box office when it hit theaters 20 years ago, Christopher Guest’s mockumentary Waiting for Guffman has become a cult hit in the years since. This movie follows a group of small-town residents-turned-amateur actors from Blaine, Missouri, and their eccentric director, Corky St. Clair, as they put on a production called Red, White and Blaine in honor of the sesquicentennial (that’s a 150th anniversary) of the town’s founding by Blaine Fabin. When they get word that New York film critic Mort Guffman is coming to their performance, they begin to dream about taking their show out of Blaine’s high school gym and onto the Broadway stage—until fate intervenes. Here are a few things you might not have known about Waiting for Guffman.

1. THE MOVIE WAS INSPIRED BY A JUNIOR HIGH PRODUCTION OF ANNIE, GET YOUR GUN.

Christopher Guest told Deborah Theaker, who plays Guffman’s Gwen Fabin-Blunt, that he was watching one of his kids perform in Annie, Get Your Gun when inspiration struck. “There were all these little kids with handlebar moustaches and he thought it was just hilarious and sweet at the same time, and wanted to translate that into a movie. That was the impetus,” Theaker said in Best in Show: The Films of Christopher Guest and Company.

“I was just drawn to the idea how earnest everyone was, how devoted they were to do the best performance they could, albeit at the level that they were working at,” Guest said in DVD commentary. “There’s something charming about the expenditure of energy to watch these amateurs.”

2. THERE WASN’T A SCRIPT …

Guest’s mockumentaries famously have no scripts. Instead, they’re entirely improvised by the actors based on outlines written by Guest and his collaborators—a tradition that began with Guffman.

Guest chose Eugene Levy, who had starred on the Canadian sketch show Second City TV (SCTV), to co-write Guffman with him. (Levy at first thought the call was a joke, but Guest was a fan of his work on SCTV.) Together, they wrote an outline stuffed with details about the story and its characters. “We provide much more information about the characters than you would find in a normal screenplay … anything that will help the actor understand who his character is and then create things on his own,” Levy, who played dentist Alan Pearl in Guffman, explained to Back Stage West. “We know what information has to come out in the movie on a scene-by-scene basis, and the actors know what information has to come out, but how it comes out is entirely up to them.”

That blueprint, Guest told The A.V. Club, is not so flexible. “What is flexible is the dialogue that's used to convey the actual exposition that we need,” he said. “Every scene has a point; it's not just people rambling. There's exposition in every scene that has to be accomplished before we can move on. And so that can't change, otherwise you have this free-for-all.”

The outline for Guffman ended up being 16 pages long, and as they were writing, some elements changed. For example, Blaine was originally in Kansas, and Corky owned a store called Over the Rainbow. In DVD commentary, Levy said that in the original outline, the cast never made it to the show; instead, a tornado came and destroyed the theater. “The camera was knocked on its side and you saw feet running by the camera,” Guest said. But after Blaine was moved to Missouri, those Kansas-centric details were tweaked, discarded entirely, or relegated to the background.

3. … BUT SOME ELEMENTS OF GUFFMAN DID NEED TO BE SCRIPTED AND REHEARSED.

Namely, the songs and dialogue of Red, White and Blaine. Guest turned to his This is Spinal Tap (1984) collaborators to help him with the music: He and Harry Shearer co-wrote “Stool Boom” and “Nothing Ever Happens on Mars,” while Guest and Michael McKean co-wrote “Covered Wagons, Open Toed Shoes” and “Penny For Your Thoughts.”

The dialogue in Red, White and Blaine is the only dialogue in all of Guffman that isn’t improvised; Guest said in DVD commentary that “writing the book for [Red, White and Blaine] was one of the most fun parts.” The cast rehearsed the choreography for the numbers over the course of four days. “It was just the right amount, because when we eventually did the show, it was at the level it should have been: Under-rehearsed, and if you watch closely, there are many things being screwed up,” Guest said.

4. MARTIN SHORT WANTED TO BE IN THE MOVIE.

Fred Willard, who plays Ron Albertson, recalled in Best in Show that Guest had run the idea for Guffman past some of his friends, including Martin Short, who had worked with Guest on Saturday Night Live and The Big Picture. “[He said] that Marty loved the idea [for the movie]. [Short] said, ‘I love it, when do I start?’ and Chris said, ‘No Martin, I want people who aren’t that recognizable.’” Famous faces, Guest reasoned, would be a distraction.

5. CORKY ST. CLAIR WAS BASED ON PEOPLE GUEST KNEW.

In 2010, Guest told Entertainment Weekly that he based Corky—who moves to Blaine after “living in New York, and working there, as an actor, and director and choreographer for 25 years or so,” as the character says—on “a compilation of people I’ve seen or met over the years, some of whom worked in regional theater. The heart of that character is how guileless he is. He has no concept of his lack of talent.” (Though some people thought Guest had to get a terrible haircut to play Corky, it was actually a toupee: “I thought it would be funny if he had a toupee. There was this box of … I’ll loosely call them wigs. It was just the silliest-looking one and clearly didn’t match the sides.”)

6. CHRISTOPHER GUEST CAST PARKER POSEY AFTER A 10-MINUTE CONVERSATION.

When it comes to casting his movies, Guest often relies on people he knows. “The characters are very much tailored for the actors and actresses … who we want for the parts,” Guest said. “You can’t train them. You can do this or you can’t.”

That said, Guest is open to new talent, and relies on informal interviews rather than auditions. "I just talk to people,” he told Back Stage West. “There's nothing to read and there's no audition. I can tell pretty fast if they can do it, just by talking to them. I make a big leap of faith and, again, it's just based on my instinct—something I get from them during a meeting.”

Parker Posey, for example, had never done improv before Guffman, but as Guest told Back Stage West, “I met [her], and about 10 minutes in I thought, Definitely.” Posey was cast as Dairy Queen employee and ingenue Libby Mae Brown.

7. FRED WILLARD TOOK INSPIRATION FOR HIS AND CATHERINE O’HARA’S CHARACTERS FROM AN ACTING COUPLE HE KNEW.

When he was starting out in New York, Willard took acting lessons from a married couple—and he used them as inspiration for Ron and Sheila Albertson, travel agents who have never left Blaine. “I don’t know that they’d ever worked professionally in their life,” Willard said of the couple, “but they had this acting workshop and you could imagine their home life.”

Willard also drew inspiration from a little closer to home. “My aunts were always drinking, and my uncles were always saying, ‘For god’s sake, put that down,’ and she’d pull away from him,” he said in Best in Show. “Our relationship was based on that. She was drunk, and I’d say ‘We need some coffee over here.’” Willard also came up with the character’s track and field background and how his and O’Hara’s characters had met before cameras rolled.

8. GUEST SUPPLIED THE SONGS, BUT THE ACTORS CAME UP WITH THEIR OWN AUDITIONS.

Though Guest gave the actors their audition songs (most of which had to be in the public domain to avoid fees), he didn’t tell them how they should audition, leaving that up to the actors themselves—so the first time he saw the auditions was when cameras rolled. “The first time we ever did it, was performing in front of the camera,” Levy said in DVD commentary. “So in essence it was more of an audition. We didn’t know if the piece we worked up was going to work, whether it was going to be funny, and not only that, we were doing it in front of a camera.”

O’Hara and Willard’s audition was based on “those coffee commercials that were on TV maybe 15 years ago where they made them almost as if they were little scenes,” Guest said in DVD commentary. “I talked to Catherine about that, and I recommended [the song 'Midnight at the Oasis'], and they came up with this.”

“We had to actually rehearse these auditions,” O’Hara recalled in Reel Canadians. “So me and Fred are actually trying to get laughs for being bad, but at the same time we had to do our choreography. Fred was so serious, he wanted to wear the towels around his neck and I was so nervous.”

Posey, meanwhile, called Guest from New York and told him she had an idea for her audition. “She sent me this two-page, single-space monologue that she wrote, asked if she could do it in addition to singing ‘Teacher’s Pet,’” Guest recalled in DVD commentary. “It’s one of the most extraordinarily bizarre scenes. For a while I had it in the movie instead of the song. I fell in love with how crazy it was.”

9. BOB BALABAN WAS SUPPOSED TO PLAY THE PIANO.

Bob Balaban said in Best in Show that when he got the call to be in Waiting for Guffman, “I had the good sense not to ask too many questions and just say, ‘Anything you want to do, let’s do that.’” But Guest wanted Balaban to play the music director—and to play the piano during the show’s rehearsals. Though he had taken piano lessons and thought he might be able to memorize the music by the shoot, Balaban ended up not feeling comfortable doing it—so instead, Guest had him train with musical director C.J. Vanston to play the conductor, and an assistant played the piano instead.

10. LOOK CLOSELY AND YOU’LL CATCH A GLIMPSE OF BETTER CALL SAUL’S BOB ODENKIRK.

He’s in the hallway during the audition scenes dressed as a vampire. Odenkirk had been cast as the town minister, but the part was cut when he had a scheduling conflict. You can see his audition in the video above.

11. THE MOVIE FILMED IN LOCKHART, TEXAS—AND A LOCAL WAS CAST FOR ONE PROMINENT AUDITION.

Guffman was shot over the course of 29 days in Lockhart, Texas, and the production cast several locals for bit parts. Most of them were cut for time, but one resident did make it into the final film in one of its most memorable auditions: an older gentleman performing both sides of an expletive-filled scene from 1980's Raging Bull.

Jerry Turman—who had previously appeared on the big screen as the chauffeur in The Best Little Whorehouse in Texas (1982)—was called in to audition for the role. To prepare, Turman said in Best in Show, “I checked out Raging Bull, and I studied the scene over and over again, and there’s no way that a guy from East Texas is going to do De Niro or Pesci—either one, so I did it in my natural voice and told [Guest] and the casting director at the beginning of it, ‘That’s the only voice I have.’”

He nabbed the part and worked on it for a few days before it was time to film. “I knew it very well, and had to learn both parts because the responses were so strange to me. We don’t talk that way here,” he said. “And sure enough when I got in, he had me do both parts. So I was prepared.” Turman had no problem with the profanity, “but I do have grandkids, and suddenly I’m aware that my grandkids are going to know about this.”

12. GUEST’S DANCING AS CORKY MADE LEVY BREAK CHARACTER.

“There’s a rehearsal scene where Corky tries to teach us that move that we just saw in the apartment,” Levy recalled in DVD commentary. “I was laughing so hard I actually worked my way to the back of the group, fell to my knees, and crawled off the set ... When these things are being improvised, you don’t want to ruin something that people are working so hard to create because find you it funny and you laugh instead of the audience laughing. The easiest thing to do is to slink off the set and let the scene continue.” (In a speech at the Austin Film Society in 2010, O’Hara recalled that “Eugene Levy would just leave scenes all the time—just go around a wall and wait” when he thought he’d break character.)

But Levy also made Guest lose it. “The idea of the lazy eye was one of the first things in the writing session that got us both on the floor,” Levy recalled in DVD commentary. “That was a very, very heavy laugh.” Said Guest: “And when you came out in the show … I said, ‘I can’t look at you, when you’re doing this thing. I’m going to look way upstage, if that’s OK.’”

(Look closely in the video above, by the way, and you’ll notice a funny detail about the jeans Guest is wearing. “I put on these jeans,” he recalled in DVD commentary, “I said, ‘These are huge, I could wear them backwards!’ And I am wearing them backwards.”)

13. WILLARD CLUED GUEST IN ON ONE IDEA HE HAD FOR THE CHINESE RESTAURANT SCENE.

Normally, the actors wouldn’t tell Guest any ideas that they had for a scene, but Willard made an exception for the Albertsons’ double date with the Pearls, where Ron reveals that he had penis reduction surgery. “I said to Chris, ‘I have an idea for something I want to do,’” Willard said in Best in Show. “Chris said, ‘I usually don’t like to know what another actor is going to do in an improvised scene, but in your case I have trouble keeping a straight face, so please tell me what you’re about to do.’ So I said, ‘I’d like to get up and drop my trousers to show Eugene my operation.’ What could be more humiliating to someone?”

14. “STOOL BOOM” WAS THE TOUGHEST NUMBER TO PERFORM.

Willard recalled in Best in Show that the hardest number to master was “Stool Boom,” which covers Blaine’s distinction as “The Stool Capital of the World” after President McKinley visited the town and took one of its footstools home with him. “Going in, all of us thought we would just play amateurs trying to dance and sing, and there was some discussion whether or not we’d lip-synch or sing live,” Willard said. “Well, much to our surprise, they brought in a woman, a choreographer, and she put us through paces like we were going to do an Off-Broadway show. We were all taken back with all these steps they had us do.” The cast had to rehearse on Saturday afternoons, and at one point, Levy hurt his foot. He “was taking aspirins and wrapping his foot, so he was in pain during that,” Willard said.

The number wasn’t just painful for the performers—the actors who sat in the audience suffered, too. “It was really tedious,” Theaker said in Best in Show. “I thought if I heard ‘Stool Boom’ one more time, I would just snap like a twig in the wind ... I thought I was going to lose my mind.”

According to Willard, “The happiest moment of shooting was when we finished filming that number, and they said, ‘Okay, cut, let’s move on.”’

15. WATCHING GUEST DIRECT IN COSTUME WAS A TRIP.

Michael Hitchcock, who played city councilman Steve Sark, recalled in Best in Show that, “The hardest thing about this was Christopher in Corky-guise giving direction, because he would still be wearing the toupee and those outrageous outfits, and he just looked so funny that it was hard not to be looking all over his body and that silly toupee while he was giving you notes.”

16. THE CAST WATCHED DAILIES TOGETHER AT THEIR HOTEL.

The cast stayed in a hotel in Austin, and, as O’Hara said in 2010, “Every night was movie night … when Chris invited us to watch dailies. You want to go to dailies on a Chris Guest movie, because we shoot 80 hours of improvisation … and then he cuts it down to 86 minutes, so if you don’t go to dailies, you miss 90 percent of the movie.”

17. GUEST HAD TO WHITTLE 58 HOURS OF FOOTAGE DOWN TO 90 MINUTES.

That meant that entire characters and musical numbers had to be cut. Frances Fisher, who played Johnny Savage’s mother, appeared in the trailer (above) but didn’t make it into the movie. Red, White, and Blaine itself ran 40 minutes long, so the numbers “Nothing Ever Happens in Blaine” (which came before “Nothing Ever Happens on Mars”) and “This Bulging River” were cut for time, and a dance sequence and solo were trimmed from “Penny For Your Thoughts.”

Editing the movie took 18 months, and Levy recalled in DVD commentary that at one point, Guest had cut Corky out completely. “In the initial edit, when you cut this thing for the first time, you had literally cut yourself out of the movie. I looked at the first cut, there was no Corky in the movie … You thought your little runs were a little too insane and maybe not grounded, and everybody said 'Let’s put them all back in, how about that.'”

18. THE ENDING COULD HAVE BEEN DARKER.

In alternate endings, Dr. Pearl ditched his wife and baby to go to Miami to become a performer; the Albertsons supplemented their Hollywood income by selling hand cream; and Corky and Steve lived together in New York. “It started on a close-up of Corky talking,” Hitchcock recalled in Best in Show, and then the camera pulled out to reveal Steve. “We were barbecuing on the roof, and we did a little limbo, so it was a little bizarre, but very funny.” But Levy and Guest ultimately ended up feeling that some of the endings were too dark, and so the epilogue of Guffman sees the Pearls living in Florida; the Albertsons making a go of the acting thing in Hollywood; and Corky back in New York City.

19. THE MOVIE HAS SOME SERIOUS FANS.

Guffman has many famous fans, including Alan Cumming (who told NPR’s All Things Considered that he could watch it “a million times”), Casey Wilson, Kristen Bell, Neil Patrick Harris, and Meryl Streep. But the film has plenty of non-famous fans, too, as Guest found out when he went on tour with McKean and Shearer. “I sang ‘Penny for Your Thoughts,’” Guest told Entertainment Weekly. “People would ask strange things like ‘Where is [Corky] working now?’ I’d say, ‘It was actually a film.’ At one of the performances, a group called the Blaine Players or the Corky St. Clair-something Society showed up. It was about 12 people, and they have meetings … Well, I don’t know exactly what they do. The movie is discussed, I guess. They had T-shirts and a lot of, well, information.” Wonder what Guest would make of the 2014 production of Red, White and Blaine that was put on in Chicago?

20. CORKY MAKES A CAMEO IN ANOTHER ONE OF GUEST’S FILMS.

Posey told The A.V. Club that when Guffman wrapped, “I had never worked in this way that felt so real and felt like family. I loved Corky so much. I was so sad to lose him. I cried in the van on the way home, and he held my hand, and I didn’t think I’d see him again.” So she must have been thrilled when Guest donned the terrible toupee to play Corky in Mascots as the coach of Posey’s character, Cindi Babineaux.