Watching the geek get the girl seems to be a national obsession in America, and nobody does geek quite like Napoleon Dynamite star Jon Heder.

Roger (Heder) is a NYC meter attendant, the type of loser who owns books entitled I'm Worth It, Darn It! and faints at the first sign of trouble.

Dr P (Billy Bob Thornton) is the unconventional motivational guru who refers to his pupils as retards and, for $5,000, promises to help Roger "release the inner lion", as well as scoop up beautiful neighbour Amanda (Jacinda Barrett) along the way.

While his first confrontation ends with his head being, somewhat predictably, put down a flushing toilet, Roger soon picks up speed - only to find that Dr P has set his formidable sights on Amanda as well.

Heder's natural kookiness, Thornton's "Bad Santa in a suit" villain and a motley crew of fellow geeks give this well-worn story an appealing makeover.

The script isn't wet-your-pants funny but support from the excellent Sarah Silverman, as Amanda's ballbreaking flatmate, plus Ben Stiller as a paranoid ex-pupil, lend comedy punches.

And an old lady face down in a bowl of jelly, a spray-painted dog and a bunch of disparate losers armed with paintball guns are always amusing.