What Happens in Vegas is the cinematic equivalent of a Twinkie: cheap, artificial, bad for you, yet eager to please and weirdly satisfying. This should not be read as an outright endorsement of industrially extruded noxious yellow snack foods, or of lazy, brain-killing formulaic date movies, simply an acknowledgement that both products serve a certain niche, and while undeniably awful, under the right circumstances they can be guiltily enjoyable.
That is to say that when compared to truly dire genre examples like Over Her Dead Body, Vegas is passable fluff, cheery enough, but ultimately disposable. While there are no vengeful ghosts or super-powered exes, it's still pretty unbelievable. The premise sounds like an Onion headline or the thesis of a college freshman's paper on rom-com clichés. Ashton Kutcher and Cameron Diaz are a match made in nitwit heaven as Jack and Joy, two witless party animals, each coming off major rejections, who meet and then bond over a night of debauchery. Only under the harsh fluorescent lights of the breakfast buffet the next morning do they realize that they hate each other; and that their quickie chapel wedding was a booze-fueled mistake. Then in the kind of twist of fate that only happens when hundreds of chimps randomly bang on keyboards until a screenplay is finished, he hits a $3 million jackpot on a slot machine, albeit with her quarter. Sooner than you can say divorce court, the dueling couple is in front of a judge (overacted with trademark smarminess by Dennis Miller), who, in a fit of temper, orders them to stick out the marriage for six months in order to claim the giant novelty check.
You can pretty much guess what comes next: They fight, they flirt, they wrestle, they do some pratfalls in Central Park, they do couples counseling with Queen Latifah, they hit each other with heavy objects, and they jump up on chairs and get a whole bar full of strangers to do a drunken sing-along with them.
All of this is about as fresh and original as a "women and men are different" stand-up routine in front of a brick wall, but the actors seem to be having a good time. To her credit, Ms. Diaz only uses her incredible booty as a special effect twice, and Mr. Kutcher manages to not look directly into the camera and "punk" somebody. Together they make for a pretty attractive, likably dumb pair. There are toilet jokes, but they aren't gross, and Rob Corddry and Lake Bell get some nice laughs as the warring sidekicks. Faint praise? You bet. But by the seriously degraded standards of the genre, Vegas is nearly a winner.