Going to Las Vegas for a ''wild'' bachelor party is now the ultimate middle-class hedonist cliché. It's not just that the jaunt has been done so often, in the movies as well as in life. It's that there's a contradiction embedded in the lure of the Vegas bacchanal. Men and women too, of course go there to be as reckless as humanly possible. But the naughtiness is so organized that there's not much recklessness left in it. Sure, you can craps-table your way to financial ruin, but the lap dances, the glorified college drinking binges, the ritualized ordering of hookers: It's all about as spontaneous as a shuffleboard tournament on a cruise ship.
The fun of The Hangover what makes it more than just one what-happens-in-Vegas romp too many is that the film completely understands all this. The four comrades who drive from Los Angeles to the Nevada desert to prepare for the wedding of Doug (Justin Bartha) aren't daring or cool; they aren't born swingers. They're an unglamorous Everyguy quartet, doing what they all think they’re supposed to do. They're probably imitating Vegas movies as much as those films imitated reality.
Phil (Bradley Cooper), the one who's good-looking enough to strut into a casino like he owns it, is a junior-high teacher devoted to his wife and kid; Stu (Ed Helms), the group dweeb, is an anxious-eyed dentist who's like the 21st-century version of American Graffiti's Terry the Toad, with a fascist girlfriend (Rachael Harris) who treats him like a slave; and Alan (Zach Galifianakis), so brick-stupid he qualifies as more nutzoid than dorkish, is a pudgy, bearded runt who stands up in the group's cruising convertible and shouts ''Road trip!'' That's an inside nod to the fact that Todd Phillips, the movie's director, made Road Trip as well, though it also indicates that these four think they're living inside a stupid teen comedy.
They arrive at their hotel, and the film then cuts to the next day, when they wake up in their trashed villa. There's a tiger in the bathroom, and a baby in the cabinet. Stu is missing his top right incisor; the groom is nowhere to be seen. And the thing is, none of them remembers...anything. The Hangover is structured, basically, as one long morning-after OMG what have I done?, and the kick of the film is that the discovery of what the characters have, in fact, done becomes the perfect comeuppance to their tidy fantasy of Vegas bliss. A light-buttered comic nightmare, like Martin Scorsese's After Hours (or Peter Berg's scandalous, overlooked Very Bad Things with things not nearly so bad), The Hangover is a riff on what the stuff you do when you're really out of control says about you.
The surprises in this movie are everything, so without giving much away, I'll just say that a Vegas chapel figures into the mix. So does a crowbar-wielding Asian gangster (Ken Jeong) who might be the epicene brother of Long Duk Dong in Sixteen Candles. There's also a juicy run-in with Mike Tyson. The Hangover has scattered laughs (many in the cathartically funny end-credit montage), but overall it's more amusing than hilarious. The most deftly acted character is Stu, played by Helms with a realistic alternating current of horror and liberation. As Alan, Zach Galifiannakis makes blinkered idiocy a cartoon rush, though a little of him goes a long way. I wish Phillips, working from a script by the knockabout team of Jon Lucas and Scott Moore (Ghosts of Girlfriends Past), had nudged the characters closer to being a true shaggy-dog Apatow-style ensemble. You're always a little too aware that they're types. But it's fun seeing each of them have the ''fun'' they deserve. B