Yes girls -- Zac goes shirtless in the first minute, followed soon after by a cute, booty-shaking dance number. And while young Mr. Efron works hard for the rest of Burt Steer's switcheroo comedy, he's never quite as dreamy and adorable as when he's boogie-ing across the gym floor. (Hey, they should make a musical about high school!) An unhappy guy in his 30s (Matthew Perry), with an unhappy wife and two unhappy teen-age children, is magically turned into a perky 17-year-old (Efron). He still has his old-guy brain, so the new young dude sets out to repair the damage, befriending his kids (now his high school mates) and making his wife (now his friends' mom) feel special. All this intergenerational canoodling veers dangerously close to icky (and pretty much defies how anybody interacts in the real world). Efron has his charms -- this is likely just an inconsequential transitional movie for him -- but the story and his life-lessons are pretty shopworn. Reno 911's Thomas Lennon, as a nerd-turned-zillionaire, offers a few laughs and the odd bit of Elvish.