Wedding Crashers

Vince Vaughn and Owen Wilson, frequent visitors to each other’s movies, have not played the leads together in one until now, with “Wedding Crashers.” Vaughn and Wilson, along with Wilson’s brother Luke, Ben Stiller, Will Ferrell — they all feel interchangeable at times, like you can put any two of them as stars of a movie and it will turn out OK.

That is the case with “Wedding Crashers,” which stars Vaughn and Wilson as two overgrown frat boys who show up uninvited to weddings, mingle with the guests, ingratiate themselves into the family, and then have one-night stands with whatever pretty young ladies they can find at the reception. Will Ferrell has a cameo, but he might just as well have been one of the stars, with, say, Ben Stiller making the cameo and Vaughn sitting this one out.

“Starsky & Hutch” had Stiller and Owen Wilson with Vaughn in a secondary role and a cameo by Ferrell, and “Old School” had Luke Wilson, Vaughn and Ferrell, “Dodgeball” had Vaughn and Stiller, and “Anchorman” starred Ferrell but had cameos by Stiller, Luke Wilson and Vaughn, and I think they were all in “Zoolander,” and do you see what I mean?

“Wedding Crashers” doesn’t do much to distinguish itself from the pack, but it is a ribald, sophomorically funny exercise in prankery. Vaughn and Wilson play Jeremy and John, two lifelong friends and divorce mediators who, by consequence of their profession, have a dim view of marriage and commitment. They live in the Washington, D.C., area, where June marks the beginning of a tremendous wedding season. With the right cover story (“We’re Uncle Ned’s kids”; “We knew Sanjay in college”; etc.) and a well-honed ability to fit in with any crowd, they spend every weekend eating free food, drinking free booze and sleeping with free women.

The event of the season is the wedding of a daughter of U.S. Treasury Secretary William Cleary (Christopher Walken). Crashing this would be like a community college dropout crashing Harvard. They boys do it, but they hit snags. Jeremy hooks up with the bride’s younger sister Gloria (Isla Fisher), who turns out to be a virginal nutcase who thinks this means Jeremy wants to marry her. And John falls for Gloria’s other single sister, Claire (Rachel McAdams), who already has a boyfriend (played by Bradley Cooper). That the boyfriend is a possessive, unfaithful jerk goes without saying; if he were likable, we’d feel bad when John eventually steals his girl, not to spoil anything for you.

Before they can stop it, John and Jeremy are whisked away on a family weekend with the Clearys to their Maryland home, where Jeremy tries to avoid Gloria and John tries to woo Claire away from her beau. At the homestead, we meet the usual tiresome variety of family oddballs, including the bitter gay son (Keir O’Donnell), the seductive, alcoholic mom (Jane Seymour), and the — heaven help us, another one of these? — foul-mouthed grandma (Ellen Albertini Dow).

The screenplay itself, by Steve Faber and Bob Fisher, should have been overhauled before being filmed. The entire last act — fully 30 minutes of the movie — is unnecessary, dragging the story along slowly to its painfully obvious conclusion. Audiences don’t mind a predictable plot if the journey is enjoyable, but this one becomes considerably less funny as it goes, milking the rift between John and Claire (after her inevitable discovery of his lies), and then between John and Jeremy, for far more screen time than they need. This is an 85-minute movie that’s been stretched into 119 minutes.

But the two leads are a good pair, Vaughn’s rapid-fire delivery nicely complementing Wilson’s lazy-surfer drawl. Bradley Cooper demonstrates he is not cut out for broad comedy as the cartoonishly evil boyfriend, but then you’ve got Isla Fisher, delightfully loony and a welcome addition as Gloria. And of course any supporting role played by Christopher Walken is fun just for his sheer, bizarre Walkennness. Walken was in “Envy,” too, you’ll recall, with Ben Stiller, as well as that great cowbell sketch on “SNL” with Will Ferrell, and — oh, never mind.

B- (1 hr., 59 min.; R, a lot of F-words and other profanity, several instances of brief nudity, some sexuality, mild fistfight violence.)