Men are from Mars, women are from Venus, and the insipid romantic comedy What Happens In Vegas takes all the attendant clichés as a given. Ashton Kutcher plays a typical dude: A lazy, overgrown adolescent who always leaves the toilet seat up, can't commit to a relationship, and seems generally content to get sloshed and wallow in his own filth. And in the overlong beer commercial that is their on-screen relationship, Cameron Diaz plays his exact opposite: A motivated, career-oriented neat freak who's ready for marriage and children, and invariably the biggest buzzkill in the room. No one could argue that this low-wattage pair belongs together—or, more to the point, deserves each other—but the gimmicky contrivances necessary to make it happen are ludicrous even by rom-com standards.
The plot is one that makes you feel dumber for having repeated it: Kutcher gets fired from a cushy job in his dad's furniture business. Diaz's commitment-phobic boyfriend dumps her the night she hosts his surprise birthday party. Both are New Yorkers and both decide to head off to Vegas with their best friends (Rob Corddry with Kutcher, Lake Bell with Diaz), where they hook up for a wild night and wind up getting married. An annulment should be easy enough to attain the next morning, except that Kutcher wins a $3 million jackpot on Diaz's quarter, so they have to go to court to decide who gets the money. But wait! The judge (Dennis Miller) freezes the cash and sentences them to "six years of hard marriage" in the hopes that they'll take their sham marriage more seriously. So Diaz moves in with Kutcher, and the games begin.
What Happens In Vegas expends a lot of energy on the pair's individual attempts to sabotage the deal and run off with the money, each of which makes them seem that much more petty and unlikable. On the sidelines, Corddry and Bell have the exact same love/hate dynamic, and they're considerably more relaxed and funny as sparring partners, mainly because they're not roasting in high-concept hell. As for Kutcher, is there any actor out there who expends so little effort to get into character? That doesn't mean his performances are effortless—quite the contrary, he goes overboard trying to ingratiate himself to the audience—but rather they whiff of smug self-satisfaction. Complain all you want about the affable slobs in Judd Apatow comedies; at least they're not tools.