Ever wondered what would result if you put Hunter S. Thompson's "Fear and Loathing In Las Vegas," a bromance-comedy of the Judd Apatow sort, and John Cassavettes' "Husbands" in a blender and hit spin? Your answer would be "The Hangover," an over-the-top comedy of men behaving badly in the absence of girlfriends or wives.

The film's story centers around an epic "lost weekend" in Vegas, with decadence that even Dr. Gonzo would be proud to call his own: Doug (Justin Bartha) is getting married and his buddies Phil and Stu (Bradley Cooper and Ed Helms) decide to take him out for a stag party in Sin City, along with Doug's soon-to-be brother- in-law Alan (Zach Galifianakis, in a role that once would have gone to John Belushi). The guys are a study in extremes: While Justin may be your basic good-husband material, Phil is a hopeless scoundrel looking to score, while Stu is a hen-pecked "nice guy," taking cell-phone calls from his controlling girlfriend every other minute. Alan for his part is an immature, awkward dweeb, who desperately wants to be "one of the guys."

"What happens in Vegas, stays in Vegas," says Doug's fiancee's father, with a wink and a nudge, but the dudes soon learn how true that is. After an absolute black hole of an evening, they wake up in their trashed hotel suite in a daze: "Why don't we remember a goddamn thing from last night?" asks Stu. "Obviously because we had a great f-cking time," says Phil. But Phil has a hospital bracelet on his wrist, Stu is missing a tooth, and Alan finds a toddler in the bedroom. And who was that lady striding out of the suite in stripper heels? Worst of all, there's a wedding to get to, but the groom has gone missing, and they face the prospect of returning without him.