In "Marci X," a cotton-candy farce about urban culture-clash, Damon Wayans twinkles with goofy good humor in the role of Dr. S., a notoriously foul-mouthed rapper whose lyrics incite the wrath of Mary Ellen Spinkle (Christine Baranski), a strait-laced U.S. senator on the warpath against smut. As this Wicked Witch of Washington, Baranski (togged out in a severe black suit and single strand of pearls), does her familiar, clenched-jawed, flaring-eyed caricature of a sputtering moralist glaring down from a high horse. The character is hellbent on holding congressional hearings that threaten to destroy the media conglomerate that owns Dr. S's record company.

With his ever-sly sense of the absurd, Wayans makes his potentially nasty character a teddy bear beneath his rapper's shell. The actor, who has refined the knack of appearing sexy and ludicrous at the same time, gives a performance of immense charm in a movie that doesn't know the meaning of street credibility. Too bad also that the movie, which plays as though it were conceived well before the ascendance of Eminem, seems hopelessly behind the curve.

"Marci X" was written by Paul Rudnick ("Sister Act," "In and Out"), who specializes in good-natured fantasies set in a hyperactive neverland of jousting bon mots. As in his other screenplays, "Marci X" is spiced with lightly barbed topical jokes and celebrity putdowns that strike glancing blows without breaking the skin. The movie was directed by Richard Benjamin, who plays Ben Feld, the media mogul and philanthropist who owns Dr. S's record company and becomes the main target of the senator's campaign. The title character is Ben's high-powered daughter (Lisa Kudrow), who vows to save her father's company when he is immobilized by a heart attack.

This is the kind of comedy in which the characters are cutouts whose abrupt changes of heart are dictated entirely by the preposterous plot and not by psychological or social reality. Determinedly optimistic, it fantasizes a giddier, sweeter world where cultural antagonisms melt at the drop of a beat. When an uptight white square catches the rhythm and gets down, he or she is immediately dubbed a "bone thug," and all is forgiven on both sides.

It's Marci's plan to win over Dr. S and convince him to apologize for his profanity on the MTV Music Awards. With three of her girlfriends, she attends one of his concerts at which he mockingly dares her to come up some rhymes on the spot. Superwoman that she is, Marci improvises a number (similar to Madonna's "Vogue")in which she drops the names of fashion designers and exalts "the power of the purse," and wins over the crowd with one exception: the rapper's jealous girlfriend Yolanda (Paula Garces).

With songs by Marc Shaiman, the composer of "Hairspray" and Mervyn Warren, "Marci X" has the tone, attitude and choreographed buoyancy of a Broadway musical, and the simplified, singalong rap songs don't aspire to radio-ready authenticity. The cleverest number is a candied ode to gay brotherhood performed by an 'NSync-like group named Boyz R Us.

"Marci X" is rated R for use of strong sexual profanity, crude sexual slang terms and racial epithets, violence (brawling and some gunplay, done for laughs) and some sexual contact. Running time: 84 minutes.