It's a concept so simple I'm amazed no one has ever done it before. Three guys take their groom-to-be friend to Vegas, spend a wild night on the Strip, and wake up the next morning unable to remember a single thing. Forced to retrieve both their memories and their missing betrothed buddy, the guys can go through a series of comedic setpieces that don't really have to fit into any kind of narrative, and so long as they eventually recover from their hangover, it counts as a character arc.
The fundamentally lazy premise of The Hangover doesn't seem to bother director Todd Phillips, who tackles the story with loose comedic timing and a willingness to follow the actors wherever they want to take it. Luckily he's picked Ed Helms, Bradley Cooper and priceless newcomer Zach Galifianakis to lead this trip, and it's what those three contribute to the largely funny script that makes The Hangover so improbably gut-busting.
The movie opens when the shit has already hit the fan, with Phil (Cooper) calling the bride-to-be (Sasha Barrese) and confessing that they might not be able to track down the groom (Justin Bartha) after all. A flashback to two days earlier sets up all the necessary character details-- Helms is a nerdy dentist terrified of his harridan fiancee (Rachael Harris), Phil is a cocky golden boy organizing the Vegas adventure, and Alan (Galifianakis) is the weirdo brother-in-law to be brought along only out of a sense of duty. The exposition is only occasionally funny and seriously slows down the momentum; things don't really get started again until the guys gather on the roof of Caesar's Palace, toast one another with shots of Jaeger, then wake up worse for the wear the morning after.
And what happens from there is really best left unspoiled, though you've probably already heard about the best parts-- the tiger in the bathroom, the Mike Tyson cameo, Heather Graham as a happy hooker, Ken Jeong as a lisping Chinese gangster who's way funnier than the character probably deserves to be. Stealing the whole thing from all the more experienced film actors around him is Galifianakis, whose dazed one liners and loopy facial expressions don't grow old even when the plot does. Whether getting tazed in the face by Rob Riggle's enthusiastic cop, peppering a steak for an angry tiger or caring for the foundling baby he dubs Carlos, Galifianakis seems to have stepped in from another movie-- another planet, even-- and lends The Hangover the only originality it has.
Because, let's face it-- even though it's about piecing things together in the cruel light of day, The Hangover is really just another entry into the "one crazy night" genre, a Superbad for grown-ups who can afford suites at Caesar's Palace. The fact that it's still funny, though, is a credit to the script's willingness to go the extra crazy mile, letting characters kick cell phones away from children, attempt to sacrifice a random acquaintance at the hands of gangsters, and pee in Mike Tyson's pool. In turn the actors toe the line between boys-will-be-boys raunch and becoming outright sociopaths, letting us wish we could be along for the fun ride but secretly knowing we want to stay 10 feet away from them at all times.
It's worth noting that The Hangover severely fails its few female characters, from the hilarious Rachael Harris as the meanie girlfriend to Graham, who is warmer and funnier in her few scenes than she's been in years, but gets abandoned to take care of the baby so the guys can continue on their adventure. Why couldn't she come along? Why can't the guys treat women as anything other than objects or the ol' ball-and-chain? Sure, this is a movie about men and their weird bonding rituals, and throwing in a token girl might have ruined the beautiful vibe between the three leads. But as another entry into the "real men secretly fear women" canon of guy comedies this decade, The Hangover feels like a continued step in the wrong direction.
And yet. If you're male or if you're female, if you're squeamish about raunchy comedy or if you love it, if you're aware of Zach Galifianakis' patented brand of absurdity or if you're new to it, you will laugh at The Hangover. You may laugh so hard that you're a little ashamed of enjoying something so silly. And after quoting all the best lines with your friends, you may still be laughing so hard that you want to see it again. Comedies this good don't happen by accident, even if a little organization could have made The Hangover much better than what it is.