That onslaught begins betimes as we're introduced to the home life of diligent but beleaguered husband and dad Dave Lockwood (Jason Bateman). Dave's sleepy middle-of-the-night effort to get his baby's diaper changed turns into the kind of revolting misadventure that might keep a somewhat backward fourth grader in stitches.

And speaking of underachieving grade schoolers, enter Dave's foil, and best friends since childhood, Mitch Planko (Ryan Reynolds). A commitment-phobic ne'er-do-well, Mitch drifts his days away with nary a care, but nonetheless envies Dave's role as a family man. And Dave, of course, reciprocates by yearning for the freedom Mitch enjoys.

When, after a night out on the town together, the two pals simultaneously give vent to their mutual jealousy while using a local fountain as a urinal—a characteristic touch—we're on to the fact, if they aren't, that tomorrow they'll wake up inhabiting each other's bodies.

For Dave that means keeping Mitch's appointment on the set of a "lorn," i.e., "light porn" movie, where he cavorts with fellow cast members of both sexes. For Mitch it involves failing spectacularly to fit in at Dave's button-down law firm, then returning home to find his long-standing ardor for Dave's wife, Jamie (Leslie Mann), suddenly cooled by her noisy, open-door use of their en suite bathroom.

And so it goes. Mitch, it emerges, has an aberrant taste for expectant mothers, a jones he indulges by trolling for talent at Lamaze classes. Dave's more orthodox appetites have him using his new persona to chase fetching law office associate Sabrina (Olivia Wilde) after whom he has long lusted.

With exquisite casuistry, Dave reasons that sleeping with Sabrina won't count as cheating on Jamie as long as he uses Mitch's body to do it.

By the time we get to an extended, late-reel joke wherein Mitch, as Dave, compares the closing of an important business deal to the successful seduction of a Catholic schoolgirl, the wearied viewer is almost too numb to be offended. Almost.

As helmed by David Dobkin, this puerile mess amounts to little more than yet another tiresome attempt to expand the boundaries of bad taste.

The film contains graphic nonmarital sexual activity, masturbation, upper female and rear nudity, drug use, repulsive scatological humor, several uses of profanity, and pervasive rough and crude language. The Catholic News Service classification is O—morally offensive. The Motion Picture Association of America rating is R—restricted. Under 17 requires accompanying parent or adult guardian.

*****
John Mulderig is on the staff of Catholic News Service.