When brainy, bobble-headed computer-toon hero Jimmy Neutron tells his mom he's contacted alien life forms in "Jimmy Neutron: Boy Genius," she's taken aback by his disobedience.

"Jimmy," she scolds, "how many times have I told you not to talk to strangers?"

It's a moment that defines the wit and whimsy of this spirited CGI kiddie creation, which is absolutely popping with personality and prodigious production design.

The cheerfully entertaining, world-saving adventure of a elementary school science geek with a Hershey's Kiss hairdo, the movie takes off -- along with Jimmy in his homemade rocket -- when those same aliens kidnap all the parents in Jimmy's town. They're to be served as sacrificial hors d'oeuvres to a colossal, three-eyed chicken-god the aliens worship upon returning to their home planet. (Yes, it's as goofball as it sounds.)

It's up to the kids to rescue their folks, of course, and the energetically eccentric, socially shunned Jimmy becomes their defacto leader when he helps the other children fashion an armada of silly spaceships out of rides at a newly opened amusement park.

Seeing roller coaster cars, a Ferris wheel and other familiar funhouse contraptions retrofitted with rocket boosters and flying through space provides a genuine sense of the joyful creative license of animation. This movie has an amazing style all its own, from Jimmy's boxy, bouncy robot dog named Goddard, with his slinky legs, plasma globe brain and the comedic ability to poop nuts and bolts, to the slime-puddle aliens who have gooey antennae-top eyes and float around in techno-funky Faberge egg mechanical bodies. (Their voices include Martin Short and Patrick Stewart, who lends copious character to the alien king.)

But it's the intrepid, undaunted enthusiasm of Jimmy himself that gives the picture its pizzazz. Laughed at for his crazy inventions that never quite make him look as cool as he hopes (a misfiring shrink-ray, a bubble-gum bubble he climbs inside to bounce to school), Jimmy's effervescent perseverance is a good lesson in overcoming frustration for the movie's adolescent target audience. Thankfully, however, director John A. Davis and his writing partner Steve Odekerk are more interested in amusing the viewer than in harping on such themes, so the movie is accessible to us grown-up kids too.

Offering less creativity in its over-simplified story and its shopworn secondary characters, "Jimmy Neutron" stops short of being an instant classic like this year's other computer animated kiddie flicks, "Shrek" and "Monsters, Inc."

But even if it isn't timeless, it is just as much fun and I'm totally gung-ho to see it again.