“A guy walks into an agent’s office and says: ‘Have I got an act for you…’” It’s a simple set-up and you know the punchline going in (hint: it’s the title of the film), but in between is arguably the filthiest, most disgusting, thoroughly depraved joke of all time, at least as explored the 100 comedians in the documentary by Paul Provenza and Penn Jillette. Among the participants are George Carlin, Drew Carey, Billy Connolly, Whoopie Goldberg, Gilbert Gottfried, Penn and Teller, Paul Reiser, Sarah Silverman, The Smothers Brothers, Steven Wright and many others.