April 26, 2002 | Since I've never been a skateboarder -- and I've always been grateful that my teen-age son isn't one, either -- I foolishly assumed that Dogtown and Z-Boys wouldn't appeal to me.

But after viewing Stacy Peralta's aggressively and arrestingly spirited film, winner of the Audience Award at the 2001 Sundance Film Festival, I'm reminded once again that some of the finest documentaries are those that can bring you to unfamiliar worlds, or immerse you in exotic subcultures, and enable you to share the enthusiasm of a filmmaker who's eager to serve as your tour guide.

In this case, Peralta is singularly well suited for the tour-guide job because he's actually one of the original "Z-Boys," street-smart wheeler-dealers known collectively as the Zephyr Skating Team. Back in the halcyon days of the early 1970s, in a rundown beach neighborhood known as Dogtown on the fringes of Santa Monica and Venice, these working-class teens and twentysomethings established their own swaggering-outlaw approach to surfing, gang-banging and graffiti-spraying. When they sampled the then-dormant skateboarding craze, they did it on their own terms, in their own in-your-face style. Which, amazingly, became the predominant style for skateboarding throughout the known universe.

Looking back with equal measures of amazement, romanticism and hard-edged melancholy, Peralta weaves a crazy-quilt tapestry of talking-heads interviews (with himself and many others), scratchy home movies, TV-news footage, mainstream and niche-audience reportage -- and lots and lots of flashy-trashy segues.

The overall style might best be described as cocksure grunge, with skittish music-video shock cuts and a brazenly up-yours attitude. (Try to imagine an entire movie that looks like the opening credits of Seven, and sounds like the playlist for a '70s-skewing golden-oldies radio station.) Sean Penn serves as off-screen narrator, and while he's plainly intrigued by the subject, he just as plainly doesn't feel the need to do much more than read his script. At one point, he noisily clears his throat in the middle of a sentence, then presses on. In a different kind of movie, that would be unforgivably sloppy. Here, however, it's all of a piece with Peralta's anything-goes approach.

Peralta, who has directed several other film and TV documentaries, offers a history lesson in which shards of imagery and testimony collide and coalesce with what only seems like randomness. Pay attention, and you'll easily grasp what's important: The rise and fall of the Zephyr Production Surf Shop where the skaters came together; the 1970s water shortage responsible for all the empty pools where the Z-Boys mastered their vertical swerves and curves; the 1975 skateboard championship where the Z-Boys set new standards with their riffing, low-slung style; the sudden fame and fortune achieved by some skaters, the obscurity and self-destruction endured by others.

Co-written by veteran photojournalist Craig Stecyk, one of the first to document and celebrate the exploits of the Z-Boys, Dogtown was financed by Vans, Inc., manufacturer of shoes favored by champion skateboarders. But don't expect a lot of product placement, or even much image-conscious revisionism. The movie makes it very clear that the Z-Boys -- along with Peggy Oki, the only Z-Girl -- were bad boys. That's what made them, and continues to make them, so fascinating.