There is a key to good'n'stupid lowbrow comedy that few lowbrow moviemakers understand, and it is this: If you have a thin but serviceable premise upon which to build cheap, vulgar, tasteless, but side-splitting dumb gags, don't slap together some insipid story clogged with clichés to prop it up -- just run with what you've got.

Don't turn your movie into Adam Sandler or Rob Schneider fodder, full of insulting attempts to make audiences genuinely feel for your imbecile heroes and wishy-washy life lessons for your stock characters to learn in the last act. Don't be an "American Pie" and backpedal on your vulgarity at the last minute with a hypocritical-apology "happy" ending.

Instead, be proudly, shamelessly, flippantly stupid, like "Harold and Kumar Go to White Castle," in which two recent-grad, odd-couple roommates don't discover anything about themselves, they never see any "bigger picture," and they don't grow up at all. They just get stoned out of their gourds on a Friday night, develop the munchies for those famous square hamburgers from the titular eastern-U.S. fast food joint, and spend the rest of the picture having preposterous misadventures while driving all over New Jersey hunting for the nearest franchise location.

But don't mistake great stupidity for a lack of character or self-awareness. It's no coincidence that these two buddies would be nothing more than token minorities in any other garish comedy -- existing only to be the butt of ethnic jokes -- and it's not by chance that their friendship is better developed than any part of the plot.

John Cho (humorously identified in the movie's trailer as "that Asian guy from 'American Pie'") plays Harold, an uptight, neatnick nerd who provides the movie's only semblance of conventional plot by being dumbstruck in the presence of a pretty neighbor whom he's too nervous to hit on. (Guess what happens at the end?)

Kal Penn ("that Indian guy from 'Van Wilder'") plays unmotivated, wisecracking, reluctant genius Kumar, who has developed a philosophy about his off-the-chart MCAT scores and family pressures to attend medical school: "Just 'cause you're hung like a moose doesn't mean you have to do porn."

Cho and Penn carry the picture with their comedic chemistry as bawdy, smarty-pants, all-American outcasts who barrel through everything from a raccoon attack (by a cheap puppet in the tradition of the "Caddyshack" gopher), to a run-in with a boil-covered tow truck driver (who invites them to have a foursome with his impossibly hot 19-year-old wife), to a bewildering hitchhiking encounter with Neil Patrick Harris. Cameos abound in this picture, but seeing the former "Doogie Howser" on a toked-up gonzo tear of car swiping, joy riding and stripper fondling is a gimmick that could have gone very wrong if director Danny Leiner didn't have a comprehensive understanding of the finer points of uncouth comedy.

Exploding stereotypes and embracing the asinine at every opportunity, Leiner (who was less successfully stupid with "Dude, Where's My Car?") throws weird, lewd jokes at every wall, and they don't always stick -- as evidenced by a handful of truly talentless supporting players and one gratuitous, near-scatological scene (far below the rest of the picture's roguish wit) which is supposed to be funny simply because the flatulent parties are pretty girls.

But the balance of "Harold and Kumar" is hilarious, and just why that's the case is hard to explain since its better gags just don't translate well to print. While unabashedly unsophisticated, this flick is subtly smarter, more audacious and more finely tuned than other movies of its ilk -- and that has a lot to do with the timing and delivery of Cho and Penn.

These former supporting players are so effortlessly droll and every-dude charismatic that this movie may just launch them out of "that guy" semi-celebrity status into a higher orbit of well-deserved stardom.