If you've seen the ads for "Honeymoon In Vegas," you've seen the funniest bits - namely, the convention of Elvis impersonators that convenes in Las Vegas as a backdrop to the film's central plot. You've also seen the big finish, namely those sky divers - "We're the Flying Elvises - Utah Chapter."

But most of the movie is just a so-so attempt at screwball comedy that would have fared much better if it were just more lighthearted. This kind of romantic farce cries out for gentility, offbeat sensibilities laced with sweetness rather than a sharp edge. In the end, writer-director Andrew Bergman ("So Fine," "The Freshman") scuttles his own intentions by rooting the movie in the cynical '90s instead of giving us a throwback to the more innocent '30s.

Still, he does have those Elvises - and, despite Elvis sightings being a rather worn-out joke, it's a funny gimmick that works in this context. (There are also some nice interpretations of Elvis songs on the soundtrack by Bruce Springsteen, Amy Grant, Willie Nelson -- even Elvis himself.)

In the film's opening, pre-credits scene, Nicolas Cage is at the deathbed of his mother (an unbilled Anne Bancroft), who coerces him into promising he will never marry. Later, this causes all kinds of guilt as Cage, a New York private eye, spends most of his time confirming his uneasy feelings about the state of matrimony by shooting pictures of cheating husbands.

But his girlfriend (Sarah Jessica Parker) wants marriage and family, so, rather than risk losing her, he suggests on the spur of the moment that they head for Las Vegas and just do it.

But before they tie the knot, professional gambler James Caan spots Parker, who is the spitting image of his late wife. Of course, he wants her, so he sets up a poker game, takes Cage for $65,000 and suggests he give up Parker for the weekend in exchange for the debt.

Soon, Caan has taken Parker to Hawaii and is proposing to her himself. But Cage catches on, heads for Hawaii and tries to win her back. (Along the way, he meets up with cabbie Pat Morita and crazy Hawaiian chief Peter Boyle, who sings Broadway show tunes at the drop of a hat.)

All of this would be enjoyable lunacy if it were clever enough, but Bergman's script merely scratches the surface of the comedy potential here. And some comic moments are undercut by his direction of the performances - Cage reaches a high pitch too quickly, Parker seems more dumb than merely confused and Caan plays his gambler with an inappropriate undertone of nastiness.

Think of the bright character actors Preston Sturges or Frank Capra could have employed in these roles without any annoying or mean-spirited edge.

"Honeymoon In Vegas" is rated PG-13 for sex, profanity, vulgarity, nudity and violence.