Time Out says
Every Saturday and Sunday, the UCB franchise’s longest-running, most beloved showcase starts when a base cast of the theater’s current top-brass—including founding UCB members Matt Walsh, Matt Besser and Ian Roberts—takes the stage. Then they introduce the surprise celebrity alumnae and friends who will be joining them (think Horatio Sanz, Ben Schwartz, Adam Pally). And finally, another special guest takes the stage, a non-improviser (think Flea, Cat Power, Rebel Wilson, Lena Dunham) who opens the show with a personal story, that’s deftly mined for laughs by the players. But you have to go to find out who’s there—that’s part of the fun. Looking for a cheap night out? Sunday shows are free, but seating is first-come, first-served, so be sure to arrive early.