When it comes to racial humour, black comedians have had a free pass for years, making white people the butt of ridicule that would send Jesse Jackson sprinting for a microphone were such stereotypical jokes directed at blacks.

Slowly, the genre pioneered by Richard Pryor and Eddie Murphy turned ugly, devolving into numbing variations of ?white people be like (insert dorky phrase/movement here)?. But now the Wayans brothers are breathing life into a stale topic with ?White Chicks.?

Based on the title plus the Wayans? over-the-top track record, I had absolutely no intention of liking this movie, let alone laughing at it. But once director Keenen Ivory Wayans and his younger brothers Marlon and Shawn proved their intention to make everyone in the movie look equally ridiculous, it proved to be strangely irresistible.

Marlon and Shawn (who share writing and producing credits with Keenen) play bumbling brother FBI agents who stumble into a gig baby-sitting rich sisters targeted for kidnapping during a weekend in the Hamptons. After tiny scratches render the two airhead heiresses unfit for public viewing, the desperate African-American agents enlist a crack makeup team to transform them into All-American princesses.

Plausible, ?White Chicks? is not. As women, Marlon and Shawn make Dustin Hoffman?s ?Tootsie? look like centrefold material. As actors, Shawn is lucky to have the far more talented Marlon to carry him. And as writers, the Wayans? plots have never strayed from the utterly predictable.

But the whole point of ?White Chicks? is to give the Wayans a platform to showcase their family brand of slapstick and one-liners. It?s a formula created by Keenen 14 years ago on his gut-busting TV show ?In Living Color? (which launched Jim Carrey, Jamie Foxx and Jennifer Lopez, among others) and continued with varying degrees of success in films like the 2000 spoof ?Scary Movie? and Marlon and Shawn?s TV sitcom.

The Wayans? tricks work best here when they lull you into complacency with extended scenes in ?white chick? character, then bust out in moments of hilariously unexpected blackness. It works least when they stoop to purely physical comedy, like Shawn?s face being smashed against a car window, Marlon tackling a purse-snatcher or Marlon?s nether regions being pummelled in an annoying variety of ways.

From 1986?s ?Soul Man? to last month?s ?Soul Plane,? racial stereotypes have been the backbone of comedies good and bad. Makeup-induced transformations are nothing new, either, whether in 1964?s ?Black Like Me? or Murphy?s phlegmy turn as an old Jewish man in 1988?s ?Coming To America?.

What makes ?White Chicks? special is the absence of conflict between black and white. Instead, the battle is between the haves and the have-mores, with the agents heating up a rivalry between their clique and a pair of Hiltonesque sisters. Bringing mother jokes, corn rows and break-dancing where they had never gone before, the agents ultimately have an empowering effect on their privileged yet insecure friends.

It would have been too easy for the Wayans brothers to use whiteface to take revenge on the legacy of Amos ?n? Andy. Instead, the only character at all interested in race is the jet-black pro athlete Latrell (Terry Crews, most recently seen in ?Friday After Next?) who?s determined to do some ?snow skiing? with the disguised Marlon.

When the brothers are finally revealed to be, well, brothers, Latrell exclaims, ?You?re not white?! ... Get this jigaboo away from me!? It?s the perfect inside-out conclusion for a movie that saves race from being just another bad punch line.

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