What Happens in Vegas is amusing enough to let slide the fact it is also idiotic, shrill, skin-deep and directed by monkeys.

Not half-bad as Ashton Kutcher movies go -- and a testament to the power of low expectations. Go in with memories of My Boss' Daughter and you might be disarmingly won over.

To be fair, Kutcher delivers one of his least grating performances -- there's no higher praise, really -- as Jack Fuller, a directionless, oversexed under-

achiever who can't even keep a job at the furniture manufacturing outfit his father owns.

Understandably distraught about being fired by the difficult-to-please patriarch (Treat Williams), Jack heads to Las Vegas for a weekend-long party with best bud Hater (former Daily Show correspondent Rob Corddry).

Also bound for Vegas -- and

similarly dejected -- is Joy McNally (Cameron Diaz), a workaholic commodities trader who gets dumped by her fiancee (Jason Sudeikis) just as she's about to spring a surprise birthday party on him. (If the idea of Sudeikis dumping Diaz is simply too outlandish to accept, consider that Kutcher gets paid to act and is

married to Demi Moore. There. Everything seems a little more possible, doesn't it?)

Once in Sin City, Joy, accompanied by her gal pal Tipper (Lake Bell, whose sole character trait is to wisecrack), discovers she's been accidentally booked into the same hotel room as Jack and Hater. From here, the two sets of friends embark on a night of drunken debauchery in which a cocktail of rejection and booze result in a quickie

marriage for Jack and Joy.

Before they can get an annulment, though, Jack wins $3 million at a slot machine with Joy's quarter. Back in New York to split the winnings and divorce, they're faced with a judge (Dennis Miller) who believes in the sanctity of wedded bliss and sentences the pair to "six months hard marriage" before they can break up.

The catch? If either walks out on the other, they lose their share of the winnings. Thus, efficient, neat-freak Joy moves in with slovenly slob Jack, each plotting to drive the other out and forfeit the cash. So thorough is Miller's

acerbic judge that he even assigns the pair a marriage counselor (Queen Latifah) to make sure they're trying to make a go of it.

The rest of the movie is a not-so-witty marathon of bickering, battling and bantering and eventual romantic collusion, despite the best interests and intentions of both parties.

None of this is anything we haven't seen countless times before in rom-com land, of course, and it would be giving the filmmakers way too much credit to say they have entertainingly tweaked a winning but cob-webbed formula.

Rather, they get by sufficiently on the charms of Kutcher and the ever-radiant Diaz who are appealing enough to sweeten the story's intrinsic mean-spiritedness and close the abundance of logic loopholes.

You could do worse.