“The Aristocrats” is a disappointment. For all the talk of how the World’s Dirtiest Joke is like some great jazz improv, which improves with each new teller’s unique voice, mostly, it’s the same joke. There’s diarrhea, there’s incest, there’s Joe Franklin and the same lame punchline.

I always thought the joke was that aristocrats (like England’s royal family) actually engage in some of the child-fucking, shit-eating acts described in the joke’s set-up. In fact, the punchline is meant to contrast the genteel evocation of the “aristocracy” with the foul deeds detailed in the joke itself. For that reason, the montage of interviews with comedians laughing at the existence of a better punchline (“the sophisticates!”) around the middle of the film is one of its funniest bits.

Likewise, when comedians digress from the established joke into hilariously ribald tangents, the film finally hits its stride. George Carlin riffs on the consistency of diarrhea, Gilbert Godfried explains the preponderance of blood in the set-up, Sarah Silverman makes it personal with Joe Franklin and damn near everyone picks on the absent Gallagher.

“Tell me a joke” would have been a better motivation for the filmmakers than “tell me the same old dirty joke.”