"Harold & Kumar Go to White Castle" is low-brow, profane, and undeniably irrelevant, but any comedy that finds a way to sneak in obscure jokes about Katie Holmes' nude scene in 2000's "The Gift" and the infectious beats of Wilson Phillips' 1990 pop hit, "Hold On," is far from stupid. This comes all the more as a surprise because of its superficial similarities to director Danny Leiner's last film, "Dude, Where's My Car?," which was likewise about two stoner friends on the search for something. That 2000 effort was more frequently moronic than funny, and its incessantly nonsensical, thoroughly dull subplot about aliens in the second half sunk whatever charm it might have otherwise had. By comparison, "Harold & Kumar Go to White Castle" also veers all over the map, a series of sketches more than a tightly strewn plot, but its raunchy R-rated source of comedy is of a richer and more fearless variety, and its two lead characters based squarely within the planes of reality.

Harold (John Cho) and Kumar (Kal Penn) are 22-year-old best friends just out of college trying to make it in the dreaded "real world." While Harold is a responsible investment banker, he is utterly bored by his job and used as an easy scapegoat so the rest of his coworkers can slack off. Kumar, meanwhile, has a chance to study at a top medical school, but his half-hearted efforts are little more than a means to satisfying his doctor father. With the weekend upon them, the uptight Harold and randy Kumar get together, smoke a bowl, and find themselves with a mouth-watering craving for White Castle hamburgers. With no White Castle in their New Jersey town, the twosome innocently head off into the night to reach the closest one in Cherry Hill. Their journey, to put it mildly, ends up becoming far more arduous and adventure-filled than either could have expected.

At first glance, "Harold & Kumar Go to White Castle" appears to be a dim-witted, trite waste of film stock, something of a distaff "Cheech and Chong" remake, but first-time screenwriters Jon Hurwitz and Hayden Schlossberg cheerfully skewer expectations. When the pals find themselves stuck in a bathroom stall surrounded on both sides by young women with explosive bowel movements, the film puts its own fresh spin on a desperate, time-worn gag that was last seen in "White Chicks." When Harold and Kumar hitch a ride with a scary tow-truck driver littered with puss-filled boils on his face and are taken back to his house, the sexually comic outcome defies the predictable norm of such a situation. And when the pair pick up former "Doogie Howser" star Neil Patrick Harris (having grand fun at playing himself), tripping on Ecstasy and horny as all get-up, the way in which director Danny Leiner handles this kooky plot turn borders on virtuoso. Throw in an escaped cheetah who gets high and takes Harold and Kumar for a reckless ride on its back; a delirious dream sequence that replaces a human wife for Kumar with a super-sized bag of weed; and a wrongfully imprisoned, brainy black man (Gary Anthony Williams) who has come to terms with his fate as a constant victim of racism, and what one has at the end is a thin little comedy that is funnier and more savvy than most.

In a gimmick that pays off, two bright actors usually stuck playing stereotypical supporting parts—Korean-American John Cho (best known as the "MILF" guy from 1999's "American Pie," 2001's "American Pie 2," and 2003's "American Wedding") and Indian-American Kal Penn (best known as Ryan Reynold's foreign exchange student sidekick in 2002's "National Lampoon's Van Wilder")—have taken over the lead roles of Harold and Kumar. Cho and Penn are a venerably offbeat team, wholly winning and ideal comic performers, and they bring a little extra to their roles by making Harold and Kumar smart, nice, real guys who simply want to have a little fun.

In a more subtle stunt that pays off, Reynolds and Eddie Kaye Thomas—the white male leads of "Van Wilder" and the "American Pie" trilogy—have been downgraded to supporting parts, with other memorable cameos coming from Jamie Kennedy (2003's "Malibu's Most Wanted"), Ethan Embry (2003's "Timeline"), Anthony Anderson (2004's "My Baby's Daddy"), and Fred Willard (better-used in a single scene than he was in his larger, wasted part in "Anchorman: The Legend of Ron Burgundy"). As Maria, the potential love interest of shy Harold, Paula Garces (2002's "Clockstoppers") is cute, but her part is minimal, at best.

For the engaging performances by Kal Penn and John Cho, who deserve to be upgraded to further leading roles; for the rib-tickling, no-holds-barred appearance by Neil Patrick Harris (2002's "Undercover Brother"), who goes out on a limb to make fun of himself and is all the more admirable for it; and for all of the arch gags and tart one-liners that work fairly consistently, "Harold & Kumar Go to White Castle" is a disaster-prone, buzz-filled trip worth taking for those turned on by knowingly ribald entertainments. Its unforced mixture of the crass with the sweet (think "Road Trip" or "American Pie"-lite) may not be the likeliest of combinations, but it is a decidedly beguiling one, all the same.