Marlon and Shawn Wayans of "Scary Movie" fame underwent hours of makeup each day to play the title characters in the gimmick comedy "White Chicks," but little good it did them. Their layers-of-latex Caucasian drag isn't any more realistic than the rubber mask worn by Michael Myers in the "Halloween" movies -- only tighter, as if their faces had been shrink-wrapped.

The two star as idiot FBI-agent brothers who keep trying to make busts without backup and botching the cases badly. Assigned to babysit two dingbat blonde heiresses -- half-hearted "Omigod!" spoofs of Paris and Nicky Hilton -- because of a kidnapping threat, Marlon and Shawn manage to screw that up too, by going undercover as the girls instead.

Giggling in Valley-gal falsettos and wobbling around the Hamptons in high heels and tight, tacky pink outfits (where, of course, everyone inexplicably mistakes them for the real heiresses), they furiously mug through every off-the-shelf cross-dressing gag known to Hollywood and supposedly "really learning something" about women in the process.

What they don't do is provide any laughs. I'm sure this kind of clowning seemed hilarious when all the Wayans were sitting around the living room of their older brother Keenan (who co-wrote and directed), drinking beers, acting mock-girly and spitballing nutty ideas. But that hardly justifies spending millions of dollars to drag out their fleeting, lowbrow mirth into an unoriginal, near-plotless movie and charge people $8 to $10 to see it.

Given the core concept, two hours and a pencil, any person off the street would come up with all the same jokes used in "White Chicks" -- G-string malfunctions, barking in surprise baritones at men who whistle, fighting off insistent paramours -- and then some.

But worse than its obvious, meager humor is the fact that the Wayans clearly couldn't care less about performances (even out of the facially restrictive makeup, Shawn can't manage more than blinking, blank expressions) or about their story making a scrap of sense -- and I'm not even talking about the inept, completely nonsensical kidnapping plot.

The guys originally go undercover when the heiresses (Anne Dudek and Maitland Ward) hole up in a hotel room because each sustained minor scratches in an accident and they refuse to be seen in public. So a crew of seven makeup people takes four hours to turn Shawn and Marlon into imitation bimbos -- instead of using all that technology to touch up the real girls in five minutes. (And if this makeover takes four hours and seven people, how do they do it themselves each morning once they're undercover?)

Those are minor, and admittedly unimportant, squabbles in a movie designed to be dumb. But when Marlon's wife (Faune A. Chambers) becomes convinced he's cheating because she catches him with a tall blonde -- and no attempt is made whatsoever to (very easily) demonstrate the truth -- even in a check-your-brain movie like this one, that's a beyond-moronic insult to the audience's intelligence and a clear case of "who cares?" script writing.

Amid the inevitable body-function jokes and subplot romances with misogynistic apology "happy endings" (Shawn falls for a gorgeous tabloid reporter who claims, in all sincerity, that "investigative journalism is my passion"), "White Chicks" does have a single fearlessly hilarious performance by rip-bodied, shaved-head brute Terry Crews (who played the prison escapee everyone is afraid of in "Friday After Next").

Essentially a macho version of the Joe E. Brown character in "Some Like It Hot," he plays a swaggering, narcissistic football star who won't take "no" for an answer from blonde Marlon. The lengths to which this actor goes for a laugh -- the complete abandonment of ego to act sickeningly love struck and, say, sing along to Vanessa Carlton's flitty chick-pop anthem "1000 Miles" -- are all that saves "White Chicks" from being completely beyond redemption.