Despite its title, "The Rocker" isn't about music.

It's about "the scene," the part of rock 'n' roll more concerned with groupies and bongs than power chords and thumping bass lines. And the guy who wants to be part of that scene more than anything in the world is Robert "Fish" Fishman (Rainn Wilson), a middle-aged drummer who missed his chance at rock superstardom by a guitar string.

As a bright-eyed, long-haired youth, he was the drummer of Vesuvius, a group about to become the toast of heavy metal. But before that could happen, Fish was canned to make room for a record executive's kin.

Two decades later, with Vesuvius on top of the charts, Fish is unmotivated, bitter and unable to keep even the most trivial jobs. Understandably frustrated, his girlfriend kicks him out of their house, forcing Fish to live with his sister, Lisa (Jane Lynch), and her husband, Stan (Jeff Garlin).

It's an ugly situation until Fish's nephew, Matt (Josh Gad), asks the aging rocker to play drums for his teen band, A.D.D. Next thing Fish knows, A.D.D. is a national sensation. But he isn't exactly cut out to be a role model.

As the kids — Gad, Emma Stone and pop star Teddy Geiger — rock their way across America, Fish demonstrates the best methods for trashing hotel rooms and fighting authority. And because the youngsters' parents aren't happy with this, it looks like everyone's dreams are gonna go south faster than a Paris Hilton single.

What happens next isn't hard to predict, but even when "The Rocker" is obvious, it's entertaining. That's because it's the sort of broad, farcical work that never takes itself seriously, nor should it. It just makes people laugh, largely thanks to Wilson.

Most people know him as Dwight Schrute from "The Office," but expect that to change. Wilson is one talented comedian, and after an hour and a half of "The Rocker," it's difficult to imagine him as anything other than a ridiculous, middle-aged metalhead with a bad knee. Wilson is the backbone of the film and, with apt direction from Peter Cattaneo, he drives it, paving the way for what could become an impressive big-screen career.

The supporting cast is solid as well, with Gad, Stone and Geiger offering fine turns as befuddled kids trying to keep their band together. Geiger gets extra points for singing all of A.D.D.'s tunes with the same verve that earned him two top-40 singles. This is important because it gives A.D.D. musical credibility, and that makes us believe in the story.

Of course, we've already established that the film isn't about music. That's just a backdrop for everything else, and everything else is delightful.