PARK CITY, Utah, Jan. 23 -- Saturday night's premiere of "The Aristocrats" was so packed that even the producers of the movie had trouble getting in, but when filmmakers Paul Provenza and Penn Jillette (Penn being the larger, talkier half of the magic act Penn & Teller) finally introduced their offering, they looked a little nervous.

Even the notes for the Sundance Film Festival warned, "This is one of the most shocking, and perhaps for some, offensive films you will ever see." "So, ahh, strap in and just have a good time," said Provenza, who suggested that the film was really about love and joy -- and 89 minutes of the most scatological, filthy, disgusting humor imaginable. The prison sentence has not yet been handed down for the crimes against nature herein described by 100 comics, including Drew Carey, Phyllis Diller, Jon Stewart, Richard Lewis, Jason Alexander, Steven Wright, Robin Williams, Don Rickles, Paul Reiser and the cartoon kids from "South Park."

Okay, kids. Now. Hand. Mommy. The newspaper.

"The Aristocrats" is a documentary about a single joke -- a joke that has circulated among comics since at least the days of vaudeville, and, as Provenza likes to imagine, maybe back to Will Shakespeare getting wiggy in a bawdyhouse in Elizabethan England.

Yet this joke is kind of a secret handshake among comedians, downright Masonic, Da Vinci Code stuff, rarely performed in public, told instead in delis, greenrooms, bars. It is a 4-in-the-morning joke. It is a joke that would make gangsta rappers blush.

All right, this is the joke: A performer walks into a talent agent's office and says, wow, does he have an act, a family act. This is the setup. It is always the same. But then the joke teller proceeds to improvise, describing -- sometimes for many, many minutes -- the father, mother, kids, pets, grandparents, and their despicable, degrading, horrible acts of interfamilial, mmm, inappropriateness.

It is like the Kama Sutra penned by the Horned One. A cruise to the Ninth Circle of Hell.

At the end of the joke -- and this part is always the same, too -- the talent agent asks: "So what do you call this act?" And the punch line is: "The Aristocrats."

Are the tellings sick? Oh, gentle reader, if we could rewind the mini-cassette tape in our minds and punch ERASE, we might. There are bodily functionalities we were not aware of. The mathematical combinations, people.

But more to the point, is it funny? Therein lies the rub.

At the premiere, a dozen attendees walked out. Others simply endured.

Yet a hundred more were so afflicted by paroxysms of laughter that they were gripping their chests and begging to be given a moment to breathe before their aortal seizures became mortal.

Kevin Pollack told the joke imitating Christopher Walken. Hank Azaria did it in a Russian accent. Andy Richter told the joke to his infant son who was wearing a Santa suit (the baby too young to understand a word). Billy the Mime acted out the joke on a boardwalk. Eric Idle did an English riff. Merrill Markoe an artistic take. Mario Cantone went for gay Italian. Richard Lewis neurotic. Judy Gold, who was pregnant at the time, did hers with pregnant people. Robin Williams wore sunglasses and did his version on the beach, while Drew Carey did his on the set (off air, of course) of his TV sitcom.

One version involved the Amish. Another, starfish. Very, very friendly starfish. There were kazoos. Hitler in a Frederick's of Hollywood getup. Midgets. Card tricks. A trapeze. Sweet Moses, they worked in the Olsen twins.

As George Carlin describes it the film, "The Aristocrats" is "the Tourette's syndrome of jokes."

So, this is never going to shown in theaters, right? We mean, excluding certain alleyways in Bangkok. Wrong. "I think they're negotiating to buy the movie as we speak," Jillette said, referring to serious film distributors. Actually, there may be multiple offers, he said.

So, it would be rated XXX? The filmmakers agree that this will be a minor Rorschach moment for our time

"The film has no sex, no nudity, no violence and no conflict. This is just people hugging each other," Jillette said. That and just words. He describes the humanity of the film as "beautiful."

This is what we learned: Jillette and Provenza came up with the idea at the Peppermill Lounge in Vegas four years ago.

Almost every comic they approached immediately said yes.

They made the film with cheap cameras. Jillette served as sound man. Provenza manned the camera. It looks like a home movie, and one of their great challenges while editing down the 100 hours of tape was that they kept hearing Jillette laughing in the background.

Provenza promises an eventual DVD release (with hours more of outtakes) that could stand as a primer for the style, approach, craft and timing of comic storytelling.

Buddy Hackett and Rodney Dangerfield both told their versions of the joke to Jillette over the phone (he didn't tape them) but were too sick to appear in the film (and soon after, they died). Jillette considers this a great loss.

While they embrace all well-told tellings of the joke, they consider Gilbert Gottfried the modern master. We remember Gottfried from his appearances on "The Hollywood Squares," but in the movie Gottfried is shown appearing at a Friars roast of Hugh Hefner, soon after the 9/11 attack. Gottfried, like other comics that night, was having trouble finding his footing in the aftermath of tragedy. And then he just went for it and told the "Aristocrats" joke.

The place exploded. Jillette compared the performance to the artistry of Picasso, Miles Davis and Stravinsky.

If and when the film is released, audiences will show whether they get the joke. As Jon Stewart put it: "Maybe it's best we don't break it down." And if people don't appreciate it? Then, Jillette said . . . well, we can't tell you what he said.