Along with The Groundlings in Los Angeles, and both Second City and iO in Chicago, the Upright Citizens Brigade Theatre is one of the premiere comedy training grounds in America. A slew of comic performers, writers, and directors have cut their teeth on the UCB stage, either at the original New York location (founded by Matt Besser, Matt Walsh, Ian Roberts, and Amy Poehler in 1996), their recent East Village addition, or their L.A. theater.

UCB has come under fire recently for not paying performers, but defenders of the organization point to the opportunities UCB provides comic minds who would otherwise have nowhere to hone their skills. Supporters of the theater maintain that by not relying on a commercial product, it can test comic boundaries in a way other houses can't. As theatre co-founder Matt Besser recently said, "We pay our performers, just not with money.”

Even those critical of the UCB business model can't deny the influence the theater has had on the national comedy scene. Many artists involved in your favorite comic television and film projects trained at UCB: selecting the twenty-five most famous performers who trained there is difficult, as so many of them go on to do great work. That's not counting comedy legends like Conan O'Brien or Tina Fey, who, while having trained elsewhere, drop in sporadically to get in on the improv action.

Whether or not you question the methods, you can't question the talent it's produced. Here are the 25 Most Famous UCB Alumni.

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Written by Brenden Gallagher (@muddycreek)