Directed by John Waters. Starring Tracey Ullman, Chris Isaak, Selma Blair, and Johnny Knoxville. Rated 18A.

John Waters has always walked a weird line between kitsch and transgression. At his best, he walks that line with the aplomb of a fire-eating ballerina; which is to say, you don't always know why you're watching him but you sure don't want to take your eyes away.

Not exactly the most deeply cinematic of filmmakers, Waters nonetheless has a distinctly personal style that has grown more refined over the years. Here, he takes the more mainstream impulses of Serial Mom and infuses them with the raunchy, gross-out spirit of his early work, with mostly hilarious (and occasionally bilious) results.

Tracey Ullman, a talent rarely well served by cinema, stars quite gloriously as Sylvia Stickles, a woman who, much to the consternation of her husband (Chris Isaak), views sexual desire pretty much the way your average Republican sees the word compassion: as something you have to pretend to like every four years or so. Sylvia, mother Big Ethel (Suzanne Shepherd), and many of the other tightlipped characters are practically wild-eyed at the incursion of homosexuals, perverts, and even the occasional liberal into their working-class Baltimore neighbourhood.

The Stickles do know something about deviance; they have a daughter, Caprice (Selma Blair), locked away upstairs for fear of taking her surgically enhanced self down to the local strip bar, where she has a rabid following. What Sylvia doesn't understand is that Caprice is a disciple of Ray-Ray (Johnny Knoxville), the Jesus of poontang. But she soon will, when a knock on the noggin' suddenly shreds her inhibitions. Fast as you can say "cunnilingus, please", she's looking for pretty much anybody to pop her long-mouldering cork.

If seeing crotches literally on fire and hearing recitations of private proclivities--mixed with images of some of them acted out by computer-generated squirrels--are not your thing, you might want to steer clear of A Dirty Shame. But viewers with even a smidgen of dismay at the rightward turn our culture has taken--who've grown intolerant of intolerance, you could put it--will chortle at the chance to blow smoke rings up the Man's ass. Unless the Man likes it too much, of course.

The movie does eventually run out of steam, or smoke, or whatever is fuelling it, and Waters settles for a here-comes-everybody ending that is more wearing than funny. But it's hard not to be won over by his unique combination of social satire, '50s tropes (including "subliminal" trickery and a trove of the antique "bawdy" songs that lurked in your parents' LP collections), and actors giving their all--in Blair's case, giving more than their all. For whatever reasons, you come away from the film thinking that the old days were probably rowdier than they let on, and the future might still be fun, even with the possibility of yet more Bush in the White House. And who knew Patty Hearst was into frottage?