There's a delightful surprise before the opening credits of "Daddy Day Care" -- a very funny CGI-animated short about tadpoles and peer pressure called "Late Bloomers."

The movie itself doesn't demonstrate half the creativity crammed into that four-minute cartoon. But it's not bad either.

Eddie Murphy stars as a workaholic ad exec sacked from his job (for promoting a kids' cereal called Veggie-Os) and saddled with taking care of his 4-year-old son (cute, uncommonly sad-eyed wisecracker Khamani Griffin) while his wife (Regina Hall) becomes the breadwinner, going back to work as a lawyer. But apparently she's a woefully underpaid lawyer because to make ends meet, Murphy turns their home into a day care center and enlists a couple laid-off buddies (pratfalling heavyweight Jeff Garlin and scatty sci-fi geek Steve Zahn) to help.

Being Fictitious Movie Males, they're largely inept at child rearing and thus are soon in way, way over their heads. But writer Geoff Rodkey and director Steve Carr (who shot Murphy's "Dr. Dolittle 2") manage to comedically freshen up what is essentially 1983's "Mr. Mom," multiplied by a dozen extra kids.

A lot of the humor comes, of course, from the children getting the best of Murphy and Garlin (while Zahn seems to operate more on their level). Living rooms are wrecked, shins are kicked -- and the fact that the actors are so clearly game for the worst of it blesses the flick with laugh-getting reaction shots that go a long way toward entertaining both kids and adults. A particularly disastrous potty-training misfire is sold entirely on Murphy's incredible facial contortions of horror as he peers fearfully into the bathroom, then down at the floor, then up at the ceiling.

Hyperactivity abounds, of course. A predictable lesson about priorities finds Murphy learning to give his own kid equal time. There are too many montage sequences set to peppy, overused pop songs like "Walkin' On Sunshine" and "ABC" (although the choice of The Ramones' "I Wanna Be Sedated" when the kids explode on a sugar high is amusingly apropos).

But Murphy and Zahn score a lot of laughs with their mugging, the child performers are well-cast (not an over-actor in the bunch), most of them with distinct personalities (instead of being generic, cue-card-quality cherubs like, say, the kids playing elves in "The Santa Clause 2"), and director Carr isn't afraid of aiming some of the comedy over kids' heads.

An uncredited Jonathan Katz (from Comedy Central's cartoon "Dr. Katz, Professional Therapist") steals a scene or two as an I-dotting, T-crossing nebbish safety compliance inspector who at one point is tricked into putting on a puppet show for the kids that turns into a hilarious therapy session as the puppets act out his messy divorce.

Where "Daddy Day Care" falters is in a few awkwardly mechanical, our-script's-too-short contrivances -- most notably the subplot involving the snooty headmistress (Anjelica Huston) of a upscale rival day-care "academy" (where preschoolers learn Latin, Tai Chi and SAT preparation) who tries repeatedly to sabotage our heroes because she's losing students to them.

Such shortcomings drag the film down quite a bit, but "Daddy Day Care" is still entirely enjoyable as Saturday matinee family fare.