There is a joke, passed down since the days of Vaudeville, rarely ever performed in public but used as a sort of knowing in-joke between comedians. Perhaps the novelty of the joke is that it begins with, "A guy walks into a talent agent's office...," ends with the two-word title phrase, and what fits in between is open to free reign for whoever is telling it. In order to work its magic, though, the joke requires the filthiest, smuttiest, crudest, most shocking content that can be imagined. The possibilities are endless, but said possibilities may just put some audience members in a state of stunned catatonia. Conservatives need not apply.

For everyone else, "The Aristocrats," directed by Paul Provenza, is a talking-heads—or should it be joking-heads?—documentary that is as tasteless as a motion picture can get, but also undeniably amusing. As the joke itself, what is and isn't funny in comedy is up to personal opinion. Likewise, the film—87 minutes of about eighty comedians telling the same joke under their own interpretation—isn't consistently a home-run. Some tellings fall terribly flat, while others build to a crescendo of laugh-out-loud hilarity. The highlights are George Carlin, who opens the film; Gilbert Gottfried, who is documented bringing the house down at the Friar's Club Roast for Hugh Hefner, daring to bring off-color, perfectly delivered humor to an event that needed it shortly after the 9/11 terrorist attacks; Billy the Mime, who wordlessly gets his point across to sidesplitting effect; and an irreverent Bob Saget, as far away from Danny Tanner as humanly possible, but throwing in a sly "Full House" jab for good measure.

Moving so quickly between the comic participants and literally never quitting with its graphic, potentially offensive dialogue, "The Aristocrats" doesn't have time to get boring. There are some lags in the laughs, but for the most part, the tone stays as light as air and the subject matter is salacious in the most fearless and entertaining of ways. What proves to be a surprise is the outline of the joke itself. When it is first revealed, the punchline comes off as anticlimactic and the whole thing just doesn't seem to work. The more it is told and diversely interpreted, however, it suddenly grows a life and depth not recognized on first hearing. The topics within the joke—ranging from masturbation to incest to bestiality to fisting to scat—are used for a very particular purpose, building and building to a payoff that, the more one thinks about it, is brilliantly ironic, satiric and ageless.

As a theatrically release documentary, seeing "The Aristocrats" on the big screen isn't essential; because it isn't visual and consists solely of people talking to the camera, it will work just as well on DVD. For the not easily offended, though, it is a movie worth seeing at some point down the road, if for no other reason than to get a glimpse at the creativity and talent it takes to craft a successful joke that can push all moral barriers and still end up oddly innocent and good-natured. "The Aristocrats," the most in-depth study of a single joke that has likely ever been attempted on film, is something of a peculiarity rather than a fully formed motion picture, but makes up for that by having sharp-tongued ingenuity to spare and a clear-cut purpose to its raunchy madness.