The idea of creating a loose plot outline and costly sets just so two goofballs can clown around and improvise onscreen might sound fun if you're the two goofballs. But it's a chore if you're a member of the audience.

That must be the sort of thinking behind "BASEketball," an extremely tasteless and for the most part unfunny parody of pro sports, starring Trey Parker and Matt Stone (creators of the cable channel Comedy Central's controversial "South Park").Admittedly, the twosome's barbs sometimes find the desired targets, and there are a handful of inspiredsight gags. But they're overwhelmed by tons of disgusting gross-out jokes and even more frighteningly stupid jokes.

Also, the humor is so mean-spirited (among those the film pokes "fun" at are short people, homosexuals, sick children and Hispanics) that no amount of charm (and these don't have that much) can overcome it.

Parker and Stone play, respectively, Joe "Coop" Cooper and Doug Remer, out-of-work buddies who invent a new sport called "BASEketball," which combines parts of basketball and baseball.

To everyone's surprise, the driveway activity takes off nationwide. In fact, it proves to be so popular that billionaire Theodore Denslow (Ernest Borgnine) creates a professional BASEketball league, which avoids the high salaries and competing egos of other pro sports. And Coop and Doug quickly become the new league's stars.

But that is threatened when Theodore dies and another team owner, Baxter Cain (Robert Vaughn), offers the duo big money. They also nearly come to blows over Jenna Reed (Yasmine Bleeth of TV's "Baywatch"), the beautiful head of a charitable foundation who wants nothing to do with professional athletes.

Co-writer/director David Zucker (the "Naked Gun" movies) based the premise on some of his real-life experiences and his "script" combines his characteristic puns and sight gags with those improvised by the two stars. Unfortunately, the vast majority of them fall flat.

And as performers, the smug and self-conscious Parker and Stone are insufferable. Also, most of the "comedic" cameo performances (including sports broadcasters Al Michaels and Bob Costas, Kareem Abdul-Jabbar and Robert Stack) are more of a distraction than anything else.

"BASEketball" is rated R for vulgar jokes (both scatological and sexual), references and taunts, profanity, male full and female partial nudity, slapstick violence and gory special effects.