To understand the movie, you have to look to the end, when it says in the credits, "No animals were fucked in the making of this film."

The audience cracks up.

The Aristocrats is the punchline for a vaudeville-era joke that starts out with people going into an agent's office and selling their act to them.

As comedy giant George Carlin says during the movie -- directed by Paul Provenza and co-produced by Penn Gillette of Penn and Teller --  the joke provides a blank slate to comics. Another says it's like a jazz piece; there's a basic structure there, but you can improvise around it and make it your own.

But generally, the emphasis is on being as dirty and disgusting as you can possibly be.

(The late Chevy Chase reportedly had parties with his comic buds to see how could stretch the joke out the longest using only four characters; the winner was one-time National Lampoon writer Michael O'Donoghue at  90 minutes).

Beastiality, scat, golden showers, incest, necrophilia ... any sexual perversion you can conceive of is fair game.

A few, like Andy Richter, even use their own infant kids as props at one point, cooing the gags to them (they're 12 or 15 months old; they don't get it).

One female comic uses her own pregnancy as a basis for the gag. Another, Wendy Liebman, spins the joke around 180 degrees and just kills with it.

(In case you haven't figured it out by now, if you think The Simpsons'  Ned Flanders is too edgy a character, or if you even have any common decency within you, The Aristocrats might not be your kind of movie).

One great scene is when Drew Carey shows the flourish he likes to end the bit with; the grins and nods that the other great comics use to demonstrate their flashes of discovery and to acknowledge his touch show how after all this time, someone can come up with a new angle that improves the joke.

Actually, according to the folklore in the movie, it was always a joke that was mainly told amongst comics, especially in the days when working "blue" just wasn't an option open to them.

That being said, Jerry Seinfeld still works clean, and one comic with a ventriloquist's dummy does a wicked parody of him.

Cartman of South Park fame even takes a crack at it with his crew as straight men (see the joke here).

Since it's relatively difficult to sexually shock any more, some comics experimented with a racial angle.

The problem with the film, as I see it, is that it's still about one joke, and analyzing one joke for 87 minutes gets a bit wearisome. I did a time check after 60 minutes.

Comedy is a risky, high-wire business, and some of the efforts flop. But when the comics hit the sweet spot, this film is screamingly funny.

I would say the film solidified my view that anger, absurdity, stupidity and cruelty are the four main pillars of comedy. :)

Bottom line: Worth seeing, but you wouldn't lose much by waiting for the DVD or for a rep theatre appearance.

PS: Think you're disgustingly funny? There's a contest one can link to from the The Aristocrats' website.