The cinematic oeuvre of Baltimore-based cult filmmaker John Waters has always been counted on to deliver a highly off-kilter, often sexually-charged perspective on any number of topics—serial killing (1994's "Serial Mom"), artists (1998's "Pecker"), and filmmaking (2000's "Cecil B. Demented") being his most recent targets—but "A Dirty Shame" goes one step further, nearly matching the explicit depravity of his reigning classic, 1972's "Pink Flamingos." The film is, at once, harmlessly good-natured and as twistedly perverse as any major picture so far this decade. Writer-director Waters will do anything, and go as far as he wants to, in his mission to make the viewer simultaneously wince and cackle with laughter. One might feel a little unclean once the 89-minute freak show is over, but, for the not-easily-offended, this is certainly one of the most deliriously ballsy comedies to hit screens in years.

Set in the blue-collar Baltimore neighborhood of Harford Road, Sylvia Stickles (Tracey Ullman) is a no-nonsense, middle-aged drug store clerk no longer interested in sex with husband Vaughn (Chris Isaak) and disgusted by her ridiculously large-breasted, exhibitionist daughter, Caprice (Selma Blair), known fondly around town by the male population as Ursula Udders. Things suddenly change, however, when Sylvia is knocked unconscious during a traffic accident, awakening as an insatiable sex addict. She is promptly taken in by Ray-Ray Perkins (Johnny Knoxville), the leader of an underground group of sex fiends who have all suffered freak brain damage. As Sylvia, Ray-Ray, and the rest of their clan set out to take over the Harford Road area and screw as many people as they can, angry retaliation comes in the form of the town's "neuters," headed by Sylvia's fed-up, crotchety mother, Big Ethel (Suzanne Shepherd).

The opening half-hour of "A Dirty Shame" is comic gold, a literally non-stop barrage of brilliantly savage sight gags and hilariously lewd one-liners. The proceeding hour is more uneven, as things go from outrageous to downright bizarre and the plotting, which too closely resembles "Cecil B. Demented" in its look at a group of deviant outcasts, becomes decidedly scattered. Even when the material doesn't always work, however, one has to admire John Waters' quirky ambition and no-holds-barred attitude, He is shameless in his juvenile mindset, and his joyful onslaught of immorality wears you into submission. Some of the time—actually, most of the time—you are so in awe at what you are seeing and hearing that conventional criticism doesn't really apply.

Tracey Ullman (2000's "Small Time Crooks") stands alongside Amy Sedaris (of Comedy Central's "Strangers with Candy") as one of the most gifted, incendiary female comics working today, and she is insanely good here as psychosexual heroine Sylvia Stickles. Ullman sees her every line delivery and every facial expression as a chance to elicit ribald laughter from the audience—even her very first line in the film, "I'm makin' scrapple!," defies description of how funny it is to hear her say it—and she fearlessly runs with it. She also has a way of making the rudest of material seem almost innocent, which is the key to Sylvia Stickles' innate likability. A conversation Ullman shares with Selma Blair (2004's "Hellboy"), courageously uninhibited as daughter Caprice, as they bond over their shared sexual appetite, is surprisingly sweet in the most flagrant form of the word.

Although "A Dirty Shame" warrants the NC-17 rating it receives, at least in regard to the MPAA's stuffy standards, it is ironic that part of the core audience who would go wild for the movie—15-to-17-year-olds—have no chance of seeing it in theaters. Save for the liberal, open-minded, and John Waters' fans, most adults will need not apply. If you don't find the sight of Tracey Ullman picking up a water bottle with her vagina while dancing to the "Hokey-Pokey" at an unsuspecting senior citizens home funny, and if the very idea of sex addicts corrupting an entire town in some of the most graphic ways imaginable isn't your cup of tea, then so be it. A fervent attack of close-vested right-wingers, and, arguably, the entire Republican Party, writer-director John Waters rightfully makes no apologies for what he has made. "A Dirty Shame" is what it is, and, regardless of whether it could be deemed "good" or "bad" (a case could be made that it is both at the same time), it is consistently, stomach-churningly watchable.