Improv has become the default activity for today’s postgraduate seekers. Illustration by Hudson Christie

I thought that I had reached an age at which I could opt out of embarrassing myself in public, but last year, of my own free will, I did something mortifying. I took a series of eight improvisational-comedy classes with the Upright Citizens Brigade, which has, in the past two decades, developed into an empire with a cultural reach rivalling that of Deepak Chopra, say, or Kanye West. One Sunday morning, dressed to aerobicize (“You should be prepared to move around, lay on the ground and stretch in various positions,” an e-mail from U.C.B. advised), I arrived at an office building on Eighth Avenue and Thirty-seventh Street, and psyched myself up to learn how to amuse strangers.

On the ninth floor, I navigated a warren of hallways, the walls lined with group photographs of U.C.B. performers of yore, among whose ranks I recognized film and TV actors—Horatio Sanz, Aziz Ansari—and also people with whom I’d gone to college. From behind closed doors came screams and chanting and the sounds of bodies hitting the ground. In Room 911, I joined fourteen young men and women; we shifted nervously in our seats, facing a black wall in front of which four bentwood chairs were lined up. Our teacher, James Dwyer—a baby-faced guy wearing glasses, a plaid shirt, jeans, and sneakers—sat down and began riffling through papers. “I’m not usually this much of a mess,” he said, mock-grimly. “I’m not going to commit to that—actually, I am.” We laughed at this—an improv joke—and at pretty much everything else that Dwyer said.

U.C.B. offers improv and sketch classes at all hours, seven days a week. A block of eight costs four hundred dollars and up. Classes usually sell out within minutes of being posted online. If you make it through Improv 101, you can take 201, then 301, and 401, after which you may apply for admission to the advanced-study program. When an improviser has completed the core curriculum, the process of auditioning for one of the dozens of house teams, which perform on a U.C.B. stage, begins. Members of house teams (who by the time they reach this point have paid at least sixteen hundred dollars to the organization) are not compensated.

A handout circulated, outlining the code of conduct. It said, “Do not: eat, drink alcohol, use tobacco products (including e-cigarettes). . . . Inappropriate sexual behavior between any members of this class (or members of the UCB community in general) will not be tolerated. . . . Don’t be a Dick.” Dwyer noted, “If it’s on the sheet, it means someone has hardcore broke it before.”

Dwyer had us warm up with bonding exercises—Zip Zap Zop, mnemonic name games (I’m Mozzarella Michelle, and you’re Energetic Erin, and you’re Egghead Emma). After every one, we gave ourselves a round of applause. Next, he asked each of us to deliver a rant. “You know what I hate? People who live in New Jersey,” a woman wearing a long Duracell-battery tank top and seemingly no pants said. “People who say the Beatles are overrated!” a guy from New Jersey, named Adam, yelled. The energy grew more manic. Dwyer tried to settle us down, paraphrasing Neil Casey, an actor and U.C.B. alum: “You want to take the slow train to crazytown.”

We learned about “agreement.” If you tell people you’re taking an improv class, they’ll inevitably make some joke involving the phrase “yes, and,” which is an improv technique that helps prevent your scenes from stalling out. The idea is to affirm whatever your scene partner has just made up, and to build on it. In life, because humans are not generally agreeable, one often defaults to “yes, but.” (“I am your improv teacher, and I’m telling you to commit to being a nun doing the Nae Nae.” “Yes, but that sounds like hell.”) Instead, improvisers are taught to make like the girls in “The Crucible”: “There’s a yellow bird!” “Yes, I see it, too, and I think it’s Mary.” “Yes! And she’s a witch!” And so on.

Dwyer then asked us to shout out phrases and to improvise short scenes based on them. Vlad, a hammy actor from Russia, kept yelling “Porn star!,” which Dwyer repeatedly rejected.

My first scene was based on the suggestion “viral YouTube video.” I followed Adam, the Beatles fan, to the front of the room, my palms clammy. We locked eyes and played a mental game of chicken. Who would crack and say something—oh, my God, anything, please—first? Adam caved and screamed a few words about having broken into a zoo, and for some reason I started to mime cranking an old-timey movie camera. O.K., we’re in a zoo! And we’ve created a new kind of cereal! Which we’re trying to sell! With this destined-to-go-viral ad campaign! Climb into that enclosure! Oops, there are Tasmanian devils in there! They’re chasing you in circles! But, don’t worry, I’m getting it all on film! And why do I have a Southern accent?

Dwyer and my fellow-students laughed along, although I already suspected that a big part of improv training is being conditioned to laugh at regular intervals no matter what is happening onstage. (Chalk it up to nervous empathy.) I retreated to my seat, aglow with pride that I did not throw up or cry. What had transpired instantly felt like a fever dream I could only half recall. When doing improv, you’re supposed to work from the “top of your intelligence,” which means responding honestly and logically to your scene partner’s prompts, but things had moved so fast that I couldn’t remember having had any thoughts at all.

“That’s the magic of improv,” Dwyer told us. “You find yourself in a place where you’re, like, how did I get here?” He added, “Oh, yeah, and if I call something dumb or stupid it’s always a compliment.”

In 1989, Spy published an article titled “The Irony Epidemic.” Its claim: “A generation’s perpetual frown had become a perpetual smirk.” At some point in the decade after David Letterman’s show and “Saturday Night Live” were launched, every insurance salesman and college kid began to believe that it was his right, and his obligation, to be funny. Comedy was no longer the specialized domain of nerds; it went mainstream and became, even, cool. Today, with YouTube and Twitter providing a constant audience, humor is anyone’s game. That is exactly the line that the Upright Citizens Brigade is peddling: If you follow our rules, you will get laughs without having to tell a single joke. Your personal life will improve, and you will get ahead in business. Just sign here, and here, and hand over your credit card. Like starting a band in the sixties, or joining a cult in the seventies, or enrolling in business school in the eighties, or going to group therapy in the nineties, taking improv classes has become the default activity for today’s postgraduate seekers.

Of course, improvisation has been around forever. From Satan’s “lying wonders,” in the Bible, to Donald Trump’s Presidential run, making it up as you go along is a durable tactic. Commedia-dell’arte troupes entertained Renaissance townspeople with plays contrived on the spot. Elaine May and Mike Nichols did it. Since the nineteen-fifties, so have the Compass Players (first under the direction of the grandmother of improv, Viola Spolin, and her son, Paul Sills) and Second City (under Sills), in Chicago; the Committee, in San Francisco; and the Groundlings, in Los Angeles. U.C.B. was hatched as a sketch group in 1990, in Chicago, and started offering improv classes in 1996, in New York.