The Aristocrats is a 2005 documentary about the funniest dirty joke which shares the same name as the film by American TV presenter Paul Provenza.
The Aristocrats is told by 100 prominent comedians including Billy Connoly, Eddie Izzard, Robin Williams who explain this transgressive and why it is only usually shared between comedians backstage.
This is generally how the joke is set up (though much of it is improvisation so hearing it from one comedian to the next it will probably sound completely different):
1 Setup: A family act going in to see a talent agent; either the whole family or just one family member (usually the father).
The agent asks what they do.
If the whole family is present, the act is performed for the agent; otherwise it is described.
2 Act: It is described in as much detail as the teller prefers.
While most tellings follow one of a few basic forms, the description of the act is meant to be an ad lib.
Traditionally, the description is tasteless and ribald. The goal is to significantly transgress social norms.
Taboo acts such as incest, rape, child sexual abuse, coprophilia, coprophagia, bestiality, necrophilia and murder are common themes.
3 Punch line: The shocked (or intrigued) agent asks what the act is called, and the proud answer (sometimes delivered with a flourish) is: "The Aristocrats!"
Even though this documentary is based around a topic that is not politically correct in the slightest, it won U.S. Comedy Arts Festival Award in 2005. The film was also banned from most TV networks due to its lude nature.