“This is like a real press conference,” he said, standing next to Matt Besser and Ian Roberts at the troupe’s Chelsea theater for the first of 396 events at the annual Del Close Marathon last weekend. “Finally!”  It’s been 15 years since these Chicago transplants brought the Upright Citizens Brigade to New York with Amy Poehler. What began in downtown sites like the Luna Lounge migrated to an abandoned strip club and eventually grew into a full-fledged comedy empire.  Besides building three busy theaters (including one in Los Angeles and a recent addition in the East Village), a bustling school and an international reputation that rivals institutions like Second City and the Groundlings, the troupe was critical in pushing improv to the center of the comedy world.  The biggest comedy stars in television (Ms. Poehler, Tina Fey, Stephen Colbert) and movies (Will Ferrell, Steve Carell, Bill Murray and Kristen Wiig) are more likely than ever before to have cut their teeth on improv teams rather than in stand-up clubs. The best work of Christopher Guest, Larry David and Sacha Baron Cohen leans heavily on improvisation. Besides a steady diet of live shows at the Peoples Improv Theater, Magnet and the Upright Citizens Brigade new improv-based television programs are in development, including “Trust Us With Your Life,” hosted by Fred Willard, which will have its premiere Tuesday night on ABC. And with the monthly “T J and Dave,” improv comedy has become an Off Broadway hit.  Yet understandable skepticism remains. How can work generated on the fly be that good? Aren’t the laughing fans who pack Upright Citizens Brigade shows grading on a curve? Is improv comedy really its own art form?  It’s an old debate, controversial even in the most storied years of Second City, the venerable training ground for John Belushi, Mike Myers and so many stars of “Saturday Night Live.” One of its founders, Bernie Sahlins, believed improv was a tool to develop material. Del Close — guru to countless comedians, longtime director at Second City and pioneer of the long-form method called the Harold — strongly disagreed and insisted it was an art form in its own right, a stance that was a simmering source of tension. When Mr. Sahlins visited Close in the hospital in 1999 on the day before he died, Close wagged his finger at him and picked up the old fight. Mr. Sahlins replied, “For tonight, it is an art form.”  Of the dozen or so troupes I saw at the Del Close Marathon, the one that made this case most persuasively was the Stepfathers, a group whose most recognizable star is Zach Woods (Gabe in “The Office” on NBC). They perform Friday nights at Upright Citizens Brigade. Their exhilaratingly inventive show zips from scene to scene, weaving together themes elegantly while always looking to upend expectations.  These veteran comedians have a facility with sharp one-liners — “You are a human apology,” Mr. Woods snapped — but what made the marathon’s show so irresistible was how it often seemed like a runaway train about to veer off course. The troupe’s Chris Gethard specializes in entering a scene and, with one line, rerouting the entire narrative. “I know you haven’t talked in 12 years and express yourself only in saxophone,” he started one scene suddenly.  Accepting and building on what your partner says is a bedrock principle of Upright Citizens Brigade improv, so this new information posed a challenge that veterans like Michael Delaney, Shannon O’Neill, Will Hines, Connor Ratliff and Silvija Ozols handled with aplomb. In a matter of seconds we were in a courtroom as a man testified by saxophone. “Objection!” the lawyer interjected. “That piece is extremely jaunty.”  There’s an earnest brand of self-awareness here that displays an understanding that improv at its best does not merely aim to simulate scripted drama. It asks the audience to see the viewpoint of the performers, what corners they talk themselves into and how they get out. The show culminates in a sped-through silent rewind where cast members mime, in reverse, the performance they just finished. Meanwhile performers pause to comment on their mistakes.  By drawing attention to the form, through dramatic twists and navel-gazing deconstructions, the Stepfathers pull off the difficult trick of inviting the audience to look critically at the mechanics of the performance while also fully investing in their comic scenario. The result is an electric, virtuoso entertainment that balances belly laughs with knowing giggles.  Another seasoned company, Bassprov from Chicago, has a lower-key, patient style that gradually builds one 30-minute scene of banter between middle-aged Indiana good ol’ boys, Donny Weaver (played by Mark Sutton) and Earl Hinkle (Joe Bill), on a lazy day of fishing. In a festival filled with monotonously overheated comedy — so many improv scenes move from violent anger to sexed-up desire back to anger again — Bassprov refreshingly has the feel of a quiet character study.  There are pregnant pauses, windy small talk and the kind of moseying banter that doesn’t strain for laughs. The troupe gets them anyway. Jokes emerge organically, using wordplay, character quirks and quicksilver wit. In their marathon shows a third character joined them. Matt Walsh, a co-star on HBO’s “Veep,” fit in beautifully with his understated, observant deadpan charm. At one point Earl’s mind wandered to a comparison between male and female serial killers. “Women prefer passive murder,” he speculated, which earned Donny’s rejoinder: “You mean marriage.”  The marathon concluded with Upright Citizens Brigade’s signature long-running show, “Asssscat 3000,” starring the four original New York members, who are all highly skilled, quick witted and intuitive. They quickly found the funny scenario in a scene, developing it and punctuating dialogue with just enough jokes. And yet there was something scattershot and rusty about their teamwork. The performers occasionally seemed to step over one another, not allowing the humor to breath.  The divide between improv and scripted comedy is often exaggerated. After all, a screenplay does not prevent playfully spontaneous performance, and there is a method to long-form improv that structures the scenes. Besides the amount of time it takes to generate ideas, the essential difference is how deeply collaborative truly great improv must be. It’s one thing to have chemistry onstage; it’s another to know your scene partners so well that you intuitively anticipate their next moves.  An art form without an author, improv comedy is sometimes compared to a high-wire act, but truly to understand the level of difficulty, imagine a team of tightrope walkers chained together. Then every few seconds one daredevil must make a sudden, dramatic move.
The Upright Citizens Brigadeâs Del Close Marathon of improv highlighted the art form this summer with nearly 400 events.