If there was a very small child whom I wanted to introduce to the magic of movies, I could do a lot worse than this harmless but rather cute action fantasy (like the very dreary action fantasy of Aliens in the Attic) about a team of guinea pig superspies out to save the world from a British arms dealer/kitchen appliance manufacturer/supervillain (Bill Nighy: Valkyrie) who wants to blah blah blah. The CGI guinea pigs are startlingly realistic-looking (voiced by Sam Rockwell [Frost/Nixon], Tracy Morgan [The Longest Yard], Penelope Cruz [Vicky Cristina Barcelona], and Jon Favreau [I Love You, Man]), even if they’re behaving somewhat out of character for small household rodents, which will charm kids, and the whiz-bang nonsense they get up to — which involves usage of cool computers, fast driving in unlikely vehicles, thwarting of evildoing, and other heroics — is exactly the stuff of silly, entertaining moviegoing. Visual FX vet Hoyt Yeatman makes his feature debut here, and the FX are indeed dazzling, too, and end up like a gentler, less sense-rattling version of the Transformers or Terminator movies little kids’ older siblings will have been talking about all summer. It’s not exactly clever — did it really take five credited screenwriters to come up with stuff like “We leave no rodent behind!” and “Little is the new big!” or all the many obvious references to MacGyver, Raiders of the Lost Ark, Die Hard, and Groundhog Day? (The flick is much closer in tone to Cormac and Marianne Wibberley’s simplistic National Treasure films than it is to Ted Elliott and Terry Rossio’s more cunning Pirates of the Caribbean series, and it bears no resemblance at all to Tim Firth’s Kinky Boots) I wasn’t overly thrilled with any of it myself, but I wasn’t ever quite bored with it, either. And Steve Buscemi’s (Igor) deranged hamster and Nicolas Cage’s (Knowing) shy mole are among some of the funniest and most touching examples of cartoon voice performances in quite a while.