But, it turned out, Silly Billy -- aka David Friedman -- had a not so silly secret. In the 1980s, his father, Arnold, and youngest brother, Jesse, were convicted of sex crimes and sent to prison. They were found guilty of sexually molesting students who came to their home in Great Neck for computer lessons.

There's more. Arnold and his boys (including a third son, Seth, who preferred not to participate in the film), had a penchant for videotaping themselves horsing around on-camera. They even taped the night before Arnold went to jail as well as Jesse standing outside the courthouse, awaiting the verdict.

However, there are a couple of other sides to this disquieting story. Interviews with the local police suggest a certain overzealousness. "You could see this wasn't exactly Fred MacMurray and 'My Three Sons,' " a detective notes, a little too pleased with his own wit.

The movie also hints that the town may have suffered from a collective mass hysteria, a la "The Crucible" or "The Children's Hour." One theory is floated: When a community identifies itself as victimized, if you're not a victim, you don't fit in.

Yet Jarecki isn't interested in making a "Free the Friedman 2!" tract (in fact, Arnold died in prison and Jesse was granted parole in 2001). The question of their guilt or innocence is left tantalizingly ambiguous.

Instead, he turns our attention to a severely dysfunctional family, merrily videotaping their own meltdown. The more we see of them, the creepier these video cutups seem. The mom, Elaine, mostly remains an off-screen presence in their little shows, a disembodied voice vainly trying to counter the rage and sarcasm spewed at her by the rest of her family. Elaine becomes a tragicomic Edith Bunker figure, ineffectually screaming back at her demon brood as they deride and attack her. At one point, her sons conclude, on camera, that it's all their mother's fault.

Child abuse? Maybe. Mom abuse? Definitely.

There's something innately disagreeable about the Friedman men, with their chorus-line kicks and goofing around to "Cheek to Cheek." At times, with its insular self-love, their cavorting seems almost lewd.

None of that changes the fact that Arnold and Jesse may have been wrongly accused. Still, their utter lack of concern over their supposed victims -- Why would they say these things? Did we inadvertently make them angry or frightened? -- adds to the documentary's uneasy effect.

What the Osbournes are to farce, the Friedmans are to tragicomedy. "Capturing the Friedmans" is a petri dish in which an infected family captures its own bacteria. Later on, after the film was finished, David told a Newsweek reporter that Jarecki had changed his documentary from one that "was probably going to help my career . . . to one which could conceivably destroy it." For once, he seems to have had things in perspective.