You might look for castles in Spain, but . . . New Jersey?

Well, it makes some sense at least if the modifier "White" precedes "Castle," in which case we know we're talking about the famous fast-food joint that serves baby burgers called "sliders" in li'l boxes that, by reputation, taste best after an evening spent sucking down giggle-weed gas.

That experience, hallowed in some precincts, hated in others, is commemorated in "Harold and Kumar Go to White Castle," which will seem a classic if you're stoned, and only slightly less funny if you're straight.

Harold (John Cho), a low-ranking investment banker, and Kumar (Kal Penn), a refugee from medical school, are smart, funny and desperate. Though the Manhattan roommates are in their twenties, the world of women in specific and adulthood in general remains largely mysterious to them. Each seems to be segueing toward someone else's idea of what their lives should be: Harold will marry an earnest Korean girl he does not love, and Kumar will obey his father's dictates and become the doctor he does not want to become.

But tonight . . . tonight, tonight, won't be just any night, tonight, there will be no morning star, they'll see their love tonight. The problem is that their love isn't a Maria (though Harold dreams of a Maria) but a Cherry Hill slider outlet.

Can it be that the Indiana ditchweed, the Assassin of Youth, the moocah, the Belyando spruce, the bammy, the wacky terbacky has addled their brains? Are they suffering from blue munchies the size of Louisiana and only greasy, postage-stamp-size burgers prettied up with onions and served on a steamed dinner-roll bun the consistency of pudding will satisfy?

Well, yes. And that is what happens. They head to Jersey in search of the 24/7 freedom and zest of a rumored White Castle somewhere north of Princeton but south of Hoboken, running into one misadventure after another and one stereotype after another. It's one of those bad-trip movies, where the longer the travelers travel, the farther they get from their destination. Each turn is a wrong turn, each decision a wrong decision. And that includes the decision to pick up a hitchhiker who turns out to be Doogie Howser, M.D. (Neil Patrick Harris in a good-sport cameo).

The movie, directed by Danny Leiner, thrives on the comfort that Cho and Penn have with each other, how perfectly they mesh and how endearing Harold and Kumar are as they approach the bliss of which there is no match, when you burp and itch White Castle's scratch. Harold is so repressed he's a patsy for work bullies and a tongue-tied idiot when he finds himself alone in an elevator with the girl of his dreams. Kumar, meanwhile, lives off his dad while secretly subverting all the med school entrance interviews (the one he has with Fred Willard in the beginning is hysterical.)

It isn't great, but what do you expect from the director of "Dude, Where's My Car?" The movie is easily the fifth, or maybe even the fourth, best ever shot in New Jersey.

Harold and Kumar Go to White Castle (87 minutes, at area theaters) is rated R for drug and sex humor, sexual situations, profanity, excessive drug usage, crimes against humanity, and bad taste in fast food.

John Cho, left, and Kal Penn head to Jersey in search of the bliss of a slider.