"Big Fat Liar" comes as a welcome -- shallow, but welcome -- breath of fresh air after one too many films featuring bathrooms, bodily fluids, pets on acid, gaseous jokes and crotch gags. After all, "See Spot Run," "Max Keeble's Big Move" and "Snow Dogs" had signaled The Degenerative Spiral of Kiddie Movie-making. Worse is the realization that the young audience would later be satiated by the smuttier offerings of "Not Another Teen Movie" and "Slackers." Written by Nickelodeon producers Dan Schneider and Brian Robbins (who coincidentally co-starred on the '80s sitcom "Head of the Class"), the film stars Frankie Muniz as Jason, who's always ready with a good lie to get out of scrapes. (Where's the English paper? Dad choked on a Swedish meatball.) His teacher (Sandra Oh) issues an ultimatum: Turn in the paper by the end of the day or take summer school. Jason whips out a story called "Big Fat Liar" and is struck en route to school by a limousine carrying insensitive Hollywood producer Marty Wolf (Paul Giamatti). Wolf gives him a ride, but Jason leaves his paper behind. No one will hear the truth this time, and Dad tells him he's lost his trust.<br /><br />Months later, Jason and best friend Kaylee (Amanda Bynes) see a movie preview for "Big Fat Liar," and head off to Los Angeles to wreak havoc on Wolf's life -- all to get a confession that he stole Jason's paper to make the film. They even gain the sympathy of some of Wolf's abused employees, including his assistant (Amanda Detmer), former chauffeur (Donald Faison), movie star (Jaleel "Urkel" White, playing himself) and stunt coordinator (a much-aged Lee Majors).<br /><br />Because "Big Fat Liar" is without the edge that his sitcom "Malcolm in the Middle" is known for, Muniz is easy to root for but doesn't have much to work with. Likewise for Bynes, who headlines her own Tracey Ullman-like sketch show on Nickelodeon. All the hamminess is given to Giamatti, whose eyes bulge and cheeks wiggle with every sneering insult.<br /><br />The film gets snaps just by attempting the high road, and should be enjoyed by its target audience (especially since most of the high jinks occur on the Universal Studios lot). But here's one head-scratcher: The message is that it pays to tell the truth. But didn't we just see Jason getting to his payback by telling white lies throughout the film? Well, at least there's no poop.