Be forewarned: this comedy bears only the faintest resemblance to the classic book and film of the same name. The prolific Baker family leave their small-town home for “the big city” (ostensibly Evanston), where dad (Steve Martin) has a new job as a football coach. High jinks ensue when mom (Bonnie Hunt) goes on a book promotion tour and dad can't handle the brood. Though undeniably safe for the whole family, it's a sloppily written film that wears its demographic calculations on its sleeve: there's silly slapstick for the little kids, a brace of teen idols (Hilary Duff and Tom Welling) for the tweeners, and Steve Martin for boomer parents, who should steel themselves for lots of scrunch-faced sentimental mugging. Directed by Shawn Levy. PG, 99 min.