Cameron Crowe's book, Fast Times at Ridgemont High, now a movie, an album and a T-shirt, tries to update "American Graffiti," but the writing's strictly off the stall. What we get is something like "Our Miss Brooks" with a super-hyped soundtrack from Irving Azoff, co-producer and 1980s rock czar.

"Fast Times," its scenes shifting to a jerky beat, exposes Phoebe Cates (who starred as the creature from the blue lagoon in the summer flop "Paradise"). The film gets an R rating because Cates doffs her top and gets crude with crudit,es. So does co-starlet Jennifer Jason Leigh as Stacy, the girl who learns The Lesson: Boys don't ask girls for seconds if they go all the way on firsts. So after losing her virginity and having an abortion, she gives up sex and starts dating the Woody Allen of tomorrow (Brian Backer).

To quote Stacy: "I don't want sex. Anyone can have sex. I want a relationship." If this is the movie's big lesson, forget sex education and start the kids on reruns of "Leave It to Beaver." The Beav's big brother Wally's got more to say than Crowe, who researched his book and screenplay as an undercover student in a California high school.

Further damage is done by debuting director Amy Heckerling, who lacks the intuition to let things flow. The actors seem rushed and the scenes incomplete. For instance, Stacy and her brother Brad (Judge Reinhold) almost build a poignant scene outside the abortion clinic. Just when they're about to show us their stuff, poof, it's off for a car crash or a football game.

The two best things about "Fast Times" are Reinhold, who's as amiable as an est graduate, even when afflicted with Portnoy's complaint; and Sean Penn as champion surfer and doper Jeff Spicoli, who's "been stoned since the third grade."

The film has rapid-fire music by Quarterflash, Stevie Nicks, Billy Squier, the Cars, Jimmy Buffett, assorted former Eagles and the Go Go's, but it hasn't got the beat we can all dance to.

High schoolers will enjoy "Fast Times," for they'll see a lot of themselves in it. Older, wiser baby-boomers probably would prefer something with more subtleties and a stronger plot, like a remake of "Beach Blanket Bingo." FAST TIMES AT RIDGEMONT HIGH -- Jenifer Cinema, NTI, Tyson's Cinema, Showcase University, Springfield Mall, other locations.