In the braying teen sports fantasy Grind, a high school jock, a doofus, a stud, and a dork so uptight he thinks that getting into college actually matters learn life lessons through skateboarding. ''We're not losers anymore -- we're a team!'' one mangy pal exults as the quartet chases after diploma-proof sponsorship deals. Eric (''Grounded for Life'''s Mike Vogel) wants someone big-time to notice his talent for grinding, as fancy axle work is known. Matt (''Rat Race'''s Vince Vieluf, best taken in small doses) wants to touch a girl's boobs -- any girl, any boobs. Sweet Lou (Joey Kern), who has already touched many boobs, wants to escape the wrath of some comely boob-owner's father. Dustin (''The O.C.'''s Adam Brody) worries about holding on to his crummy minimum-wage job to save money for his continuing education, but one of his hilarious buddies gets him to lighten up by tossing the nerd's college guidebook out a car window.
It's a virtually adult-free universe these dudes inhabit, and any parents who wander in are ridiculed, either as literal clowns (Randy Quaid in circus makeup) or figurative ones (Christopher McDonald in a playboy bathrobe). Not exactly adult but long out of school, Tom Green makes a guest appearance as a trippy skate-shop owner; other passing brand-name X-treme comics include Bobcat Goldthwait and various ''Jackass''-ers.
Hustling for a piece of the cult interest in ''Dogtown and Z-Boys,'' Stacy Peralta's cool 2001 documentary about the 1970s SoCal origins of the showy sport, ''Grind'' supplies stretches of actual skating footage by pros doubling for the stars. It's in these moments, freed from the earthbound pull of its market-tested components, that the movie briefly relaxes into the sheer thrilling audacity of flying into the air propelled by a board on wheels.