In the final shot of “Wedding Crashers,” the Washington Monument thrusts proudly into the sky, a gargantuan phallic symbol. This randy coda sums up this inappropriate epic, a film that isn’t child-friendly, aimed at all ages, or fun for the whole family. “Wedding Crashers” is about sex.

More than that, this sex comedy makes you realize just how sexless the rest of comedy had become. Comedians are notoriously neuter – who on earth would want to sleep with Rodney Dangerfield, Jerry Seinfeld, or Jim Carrey – and ever since stand-ups started becoming leading men, Hollywood comedies have been, too.

This trend can be traced back to movies like “When Harry Met Sally,” which transformed on-screen adult relationships into sexless displays of neurosis. “There’s Something About Mary” has the sexual maturity of a 13-year-old boy. There seem to be no options other than sniggering bathroom humor and doe-eyed sentimentality.

“Wedding Crashers,” by contrast, is filthy dirty. The film harks back to the original comedies of ancient Greece, outbursts of obscene humor, during which enormous phalluses were paraded through the center of town. Only here the parade has been replaced by a multimillion-dollar marketing campaign and the phalluses by Owen Wilson and Vince Vaughn.

The two play a pair of divorce mediators whose hobby is crashing weddings and hooking up with the bridesmaids whose hormones have been revved up, and resistance lowered, by exposure to the marriage ceremony and booze.

The two happy hedonists are introduced in a manic montage of wedding crashing scored to “Shout,” a lousy song that nevertheless gets your adrenaline pumping. It’s like the lines Mr. Wilson and Mr. Vaughn use to score with their taffeta-clad targets: unbearably bad but inexplicably effective.

After making the beast with two backs with a succession of topless bridesmaids, Mr. Wilson and Mr. Vaughn end the wedding season slightly sozzled, hanging out on the steps of the Lincoln Memorial as the sun comes up, wondering if maybe there’s more to life. Mr. Wilson, in particular, feels they might be a little long in the tooth to keep plundering bridal parties.

Like the guy in the heist flick who wants to go straight, however, he agrees to take on just one more job: crashing the wedding of the daughter of the secretary of the Treasury, William Cleary (Christopher Walken). And, as anyone who’s seen a movie in the last 70 years knows, it’s the last job where everything goes wrong.

No sooner have our randy revelers crashed the wedding than Mr. Wilson feels a tugging in his heart for Claire (Rachel McAdams), the sassy, straight-talking middle daughter, and Mr. Vaughn feels a tugging somewhere else for Gloria (Isla Fisher) the secretary’s youngest daughter, whom he promptly deflowers. A series of lightly contrived incidents sees the two men invited to Secretary Cleary’s weekend home, which turns out to be a WASP house of horrors.

Not since “Fahrenheit 9/11” has a movie displayed such utter contempt for the thin-blooded, rich, white people who run our country. The Secretary’s wife is a raunchy Dr. Quinn, Menopause Woman (Jane Seymour); his mother is a foul-mouthed geriatric; Claire’s fiance is a proto-fascist Washington insider; and his son is a tortured, gay painter. This whirling vortex of social discomfort and sexual humiliation should remind every viewer of the last time they spent a weekend with their own families.

There’s been a small renaissance in American comedy recently, and Messrs. Wilson and Vaughn are two of its most able practitioners. Mr. Wilson specializes in total insincerity; where some actors have bedroom eyes, he seduces with his bedroom nose. Mr. Vaughn is a hyperverbal hysteric who spews words like a shaken up seltzer bottle, his escalating rants lifting you to giddy heights. They make a great pair.

With all its talk of oral sex, nude male and female flesh, and bedroom hopping, “Wedding Crashers” not only rejuvenates comedy but is also the most erotic movie on the market. It does sag in the third-act, and Mr. Vaughn and Mr. Wilson exhibit all the joie de vivre of wet cats as they plod through the “heartfelt” portion of the film. But the movie rallies at the last minute, squeezing in some refreshingly tasteless material about crashing funerals.