This is Penn Jillette (of Penn and Teller) and Paul Provenza's film exploring one of the most famous dirty jokes in the world. The format of the joke is:
1. A family goes into a talent agent trying to get representation.
2. They do loads upon loads of unspeakable acts.
3. The talent agent asks "What do you call an act like that?!" and they say "THE ARISTOCRATS!"
Anyway, this film is explores the history of the joke as well as various other aspects of it and comedy in general, and, naturally features a million different tellings of the joke by all sorts of people. My favorite might be Sarah Silverman's, but Bob Saget's is good as well, and Gilbert Gottfried's version is a popular favorite.
Anyway, definitely a film to check out. I love it. When I saw it, it was at a festival and while there were a couple of walk-outs, for the most part no one in the theater could breathe from laughing so hard.