Only the Weinstein Company would sink so low as to advertise Michael Cera as the star of “Extreme Movie.” Though it makes sense to highlight his involvement because he’s the biggest name in the cast, his role is so small that it doesn’t deserve more than a special guest credit. Granted, his brief appearance is the funniest thing about the film (a cybersex chat turned rape fantasy gone wrong), but it’s shady marketing nonetheless. If anyone is the star of “Extreme Movie,” it’s former “Punk’d” player Ryan Pinkston, who plays a geeky virgin looking to score with his high school crush. His story is the closest thing to a plot in the movie, but even that’s stretching it. Most of the film’s 75-minute runtime is made up of a series of sketches involving a group of sexually active teenagers. Andy Milonakis falls in love with an adult sex toy in one of the more clever vignettes, while Matthew Lillard plays himself in a series of uncouth “The More You Know”-styled sex education commercials. With the exception of Cera’s portion, though, most of the film is a mess – which isn’t surprising when you consider that no less than 10 different writers have been credited for the screenplay. Directors Adam Jay Epstein and Andrew Jacobson may be responsible for one of the best spoof movies of its generation (“Not Another Teen Movie”), but now they’re guilty of making one of the worst.