The jury's still out on whether Rainn Wilson (2007's "The Last Mimzy") has what it takes to make the transition from his acclaimed work on TV's "The Office" to leading film roles. He certainly tries hard enough and is less than inhibited, but in "The Rocker" he comes off as a poor man's Jack Black, Will Ferrell and John C. Reilly all rolled into one. In other words, he doesn't really bring anything new to the table that those actors haven't already brought to a load of similar comedies. If Wilson is only adequate, in many cases trying too hard for laughs that don't arrive, then it is with luck that the rest of "The Rocker" is as pleasant and amiable as it is.

In 1986, drummer Robert 'Fish' Fishman (Rainn Wilson) was just about to be catapulted to the big time with heavy metal band Vesuvius when his fellow mates abruptly dropped him in exchange for a record contract. Twenty-two years later, Fish is listless, middle-aged and still just a tad resentful at the way his life has turned out. When he loses his office job and his girlfriend (Jane Krakowski) on the very same day, his sister (Jane Lynch) and brother-in-law (Jeff Garlin) agree to put him up until he gets back on his feet. Through a twist of fate, Fish finds himself in garage band A.D.D. with teenage nephew Matt (Josh Gad), lead singer and lyricist Curtis (Teddy Geiger) and bassist Amelia (Emma Stone) when their previous drummer drops out. After an online jam session makes its way to YouTube and explodes with the viewing population, A.D.D. takes off and starts touring. This is everything Fish always wanted, but his stunted youth threatens to get in the way of what should matter the most: the music.

"The Rocker" is a music-centric comedy—think a lesser 2003's "The School of Rock" by way of 2000's "Almost Famous"—that makes up for a lack of gut-busting moments simply by being genial and smartly written. The film may generate more smiles than outward laughs—the funniest scene finds Curtis' mom, Amanda (Christina Applegate), coming up with a zinger of an anagram to stave off an oily guy's corny advances—but director Peter Cattaneo (1997's "The Full Monty") and screenwriters Maya Forbes and Wally Wolodarski have crafted a diverting enough story and characters that it doesn't really matter. The fun is in watching the whirlwind rise to stardom of A.D.D., a rock band that, on the catchy, melodic evidence here, is good enough to produce an actual record. Matt, Curtis and Amelia are fictional, but they're also valuable role models—with supportive parents and solid upbringings, they are teenagers who seemingly have no interest in the darker, alluring underbelly of fame and are all about the music that they play. At the same time, they are flawed people and have insecurities just as anyone does. It's really rather refreshing to see.

Rainn Wilson is well cast as Fish, a man who gets a second chance at what he's wanted all along, but there's also no denying that he's an oddball of a character actor whose charisma is one shade away from turning slimy. Although he earns the redemption that he receives by the end, Fish isn't the most palatable of lead characters. As Curtis' mom Amanda, who joins them on their performance tour and strikes up a friendship with Fish, Christina Applegate (2004's "Surviving Christmas") gives her borderline-thankless role a deeper sense of levity when it is revealed that a teenage pregnancy derailed her own musical aspirations seventeen years ago. She's fun to watch no matter the project.

As A.D.D. band members Matt, Curtis and Amelia, Josh Gad (2008's "21"), newcomer Teddy Geiger and Emma Stone (2007's "Superbad") hold their own and in a lot of ways are more memorable than Wilson's Fish. Gad looks a bit long in the tooth to be playing a high school kid, but his personable vulnerability as Matt overcomes the age issue. Geiger is a natural, unforced talent as Curtis, exposing a soulful side through the songs he writes. And Stone is simply bewitching as Amelia, a loyal gal that anyone would be lucky to have as a friend. In what feels like a continuation of their parts in 2004's "Sleepover," Jeff Garlin (2008's "Strange Wilderness") and Jane Lynch (2006's "For Your Consideration") are underused as Matt's parents, foiling their comic capabilities in the process.

"The Rocker" culminates in a giant concert, with A.D.D. opening up for headliner Vesuvius, much to Fish's chagrin. When Fish comes face to face with his old band members for the first time in twenty year, only to recognize them for the shallow, ugly phonies that they are, the script surprises in the mature way Fish handles them. When a dumber movie probably would have gone over-the-top, director Peter Cattaneo understands that less is sometimes more. He cooks up a warranted comeuppance for Vesuvius, to be sure, but it occurs differently than the viewer anticipates and is all the better for it. Also of note is the dynamic on-location shooting in Cleveland, Ohio, an attractive city that is a happy change of pace from the usual cinematic stomping grounds of Los Angeles and New York. "The Rocker" is a minor, feel-good entertainment. It's not rocket science, but its heart is in the right place.