Don't confuse such praise with high-mindedness. The flick certainly isn't above the obligatory gross-out, whether it be a geriatric backside or a sudden bout of vomiting, but Phillips and the screenwriting team of Jon Lucas and Scott Moore ("Ghosts of Girlfriends Past") are smart enough to base the debasing in well-drawn characterization and narrative.

REQUISITE COOL DUDE
Doug (Justin Bartha, "National Treasure: Book of Secrets") is getting married in two days, and so best friends Phil (Bradley Cooper, "He's Just Not That Into You") and Stu (Ed Helms, TV's "The Office") take him to Las Vegas for a final blowout. Phil, a married schoolteacher, is the requisite cool dude who isn't quite as cool as he thinks. Stu, a mild-mannered dentist, is henpecked by a shrewish girlfriend (Rachael Harris, "The Soloist"), who is under the false belief that the guys are going to Napa Valley for a wine-tasting tour. Tagging along with the chums is Alan (Zach Galifianakis, "What Happens in Vegas"), Doug's mentally unstable, soon-to-be brother-in-law who appears to have some troubling traits. "I'm not supposed to be within 200 feet of a school "¦ or Chuck E. Cheese," he mentions in passing.

They check into Caesars Palace and toast to a night they'll never forget. Cut to the following morning. Phil, Stu and Alan wake up with supreme hangovers in a thoroughly trashed hotel suite. A tiger is in the bathroom, a baby's in the closet. Stu is missing one of his front teeth and Doug is nowhere to be found. None of them can remember anything that transpired the night before. From these grotesqueries, "The Hangover" fashions a shaggy-hair-of-the-dog mystery, as the trio pieces together the previous night in hopes of finding the groom.

Part of the film's success is its terrific casting. As Stu, Helms spirals into sheer panic without losing believability, and his conspicuously missing tooth adds the right pitch of "Deliverance"-styled delirium. There are memorable supporting bits by Heather Graham ("Miss Conception") and Rob Riggle ("Step Brothers"), but it is Galifianakis who comes close to stealing nearly every scene. He imbues Alan with a childlike innocence as endearing as it is sociopathic.

"The Hangover" loses a bit of steam in the final third, when Mike Tyson turns up for a cameo and the movie's dark comic riffs opt for safer ground. But then the film acquits itself with a brilliantly wicked end-credits montage. Director Phillips hasn't topped his own "Old School," but he comes mighty close. And like any whopper of a hangover, the best remedy is to see it again.

"”Phil Bacharach