Surprisingly well-acted for a lowbrow buddy movie, “Harold and Kumar Go ToWhite Castle”freshens up a stale genre with clever writing, charismatic performances, and a hilarious supporting role by Neil Patrick Harris.This 90-minute burger commercial is crude and sometimes silly, but it’s also exceptionally funny. And it’s an enormous improvement over director Danny Leiner’s previous film, the humorless “Dude, Where’s My Car?”

The plot is simple. Two stoner friends, the anal Harold (John Cho) and his laid-back roommate Kumar (Kal Penn) get high, get hungry, and make a pilgrimage to White Castle to fight their near-terminal case of the munchies. That’s not as easy as it sounds: Along the way they are distracted by a couple of gassy college nymphs, a boil-afflicted truck driver (“Oz’s” Chris Meloni), and the sexcrazed,coke-snorting character played by Mr. Harris.

Mr. Cho is saddled with the straight man role here, and isn’t allowed to show off his comic chops the way Mr. Penn does. But considering how much I loathed him in “Van Wilder,” Mr. Penn’s performance seems natural and cool. Like Mr. Leiner, he appears to have found his footing as his career has progressed.

The film distinguishes itself most noticeably from others of its ilk by giving its lead to a couple members of ethnic minorities, who show themselves capable of being as stupid and sophomoric as any white person. Would you like fries with that?