Contrary to its title, Jackass the Movie is hardly one at all. Though feature-length (barely), it's essentially nothing more than a scattershot compilation of stunts and bad behavior either too ambitious or too disgusting for MTV. How scattershot? Consider Wee-Man's abbreviated human-pinball routine, the context-free cameo by bewigged funnyman Rip Taylor, and the lack of any rousing climax. It's still a hoot, though, and serves to reveal just how seriously these guys take their stupidity. Most folks already know where they stand regarding this kind of ''entertainment.'' But as a graphic update of Benny Hill's crotch-bopping follies, ''Jackass the (Sorta) Movie'' had this reviewer cackling like a 12-year-old on nitrous.