So-so comedy will amuse young Efron fans, but not parents.

Mike O'Donnell (Matthew Perry) is at a crossroads: Facing 40 and an impending divorce from the high school sweetheart (Leslie Mann) he married when they found out she was pregnant, he longs for another try at greatness.

A mysterious janitor grants his wish, magically returning him to his 17-year-old self (though not sending him back in time) -- a teenager whose future seems bright with the promise of popularity, possibility, and a basketball scholarship. But, as Mike discovers, the past has a way of looming large, clouding the present and ruining the future. Is it too late to undo the damage?

Face it: We've seen this movie before. The storyline's so familiar ("Big," anyone?) that it's practically its own genre. Fine acting from the cast, especially Efron, helps "17 Again" rise a bit above the banality. As the young Mike, Efron is indisputably watchable, emitting charisma from every pore. He's game, too, giving himself over to scenes that could have played tepidly and awkwardly -- Mike the teenager fending off the advances of his own daughter, who's not aware he's her dad, for example -- but generally don't. (Runner-up awards go to Mann and Thomas Lennon as older Mike's proudly nerdy friend Ned Gold.)

But good acting doesn't automatically make for a good movie, and, as directed by Burr Steers (who's helmed such deliciously subversive titles as "Weeds," "Big Love," and "Igby Goes Down"), "17 Again" lacks edge and originality.

Yes, there are jokes about cougars and "Lord of the Rings" fanatics, but that's small potatoes. And though it's good to see Perry on the big screen again, he's woefully underused. Anyone over 12 or 13 is also likely to roll their eyes at the movie's "High School Musical" references (the opening, which includes glimpses of a sweat-drenched Efron shooting hoops, practically threatens a song-and-dance number). It's clearly a play for the HSM audience, but it ends up feeling like a cheap -- and unnecessary -- shot.

Bottom line? Unless you're a die-hard Efron fan, if you go, don't go with high expectations.

Parents Need to Know

Parents need to know that they may want to think twice before letting young tween "High School Musical" fans see this PG-13 rated comedy, which is edgier than most of star Zac Efron's previous work.

There's a scene of teens drinking at a party and a fair number of sexual references. It's generally more talk than action, but there's some making out, a teen girl gets pregnant, and one character hoards condoms.

But curse words are few and fairly mild ("ass" and "bitch") and violence is at a minimum (of the two "fight" scenes, one is cartoonish, the other lukewarm). Parents may appreciate the fact that Efron's character implores his fellow teens to make so-called "smart" decisions about sexual activity and college.

Families can talk about what this movie teaches teens about the importance of their behavior and decisions, particularly when it comes to things like sex. Are those messages clear amid the comedy? Is it easier to hear those messages from Zac Efron than from parents? Families can also talk about the ongoing popularity of movies about adults revisiting their younger years. Why is that kind of story so appealing? How does this movie compare to others in that genre?

Studio: New Line Cinema Director: Burr Steers Cast: Leslie Mann, Zac Efron, Matthew Perry Genre: Comedy Run Time: 98 minutes Theatrical Release: 4/17/2009 MPAA Rating: PG-13 MPAA Explanation: language, some sexual material and teen partying

Reviewed by S. Jhoanna Robledo.

See more about "17 Again" at Common Sense Media.