Every now and then, a movie comes along that looks so spectacularly, cosmically bad that you fear for the sanity of its producers. What Happens in Vegas ...? Nothing surprising. It's a clunker of a title, and the film's premise — career woman Cameron Diaz and laid-back, laid-off Ashton Kutcher meet cute in Las Vegas, drink themselves silly, get married, and promptly win $3 million in a slot machine — strains credulity, to say the least. During a custody battle over the money, an activist judge played by Dennis Miller sentences the two to "six months' hard marriage," which somehow entails Diaz moving her smoothie machine into Kutcher's apartment while the young couple endures weekly marital therapy with Queen Latifah. There's not much here that makes sense — why is Kutcher's unemployed carpenter living in a sweet Dumbo apartment, while Diaz's hard-driving Wall Street type is homeless? — but the stars, despite having only a fraction of the charm and talent of classic sparring-but-meant-for-each-other duos, know how to mug for the camera and well up on cue, and somehow that turns out to be enough to carry this trifle. Charming Brooklyn location shots help things along, as does Rob Corddry, who, as Kutcher's best friend cum lawyer, is crafty enough to cancel out his buddy's guileless, cowlike brown eyes.