Home(s) for the holidays

Here's what I don't get: Comedies like "Christmas With the Kranks," "Deck the Halls," and now "Four Christmases" drag us through a living hell of seasonal dysfunction and loathsome relatives and expect us to spend $10 a seat for the privilege? At best, these movies are exercises in masochism. At worst - well, why pay for something you can get at home for free?

"Four Christmases" is essentially "Meet the Parents" quadrupled: Kate (Reese Witherspoon) and Brad (Vince Vaughn) play a San Francisco couple whose three-year relationship is thriving precisely because they haven't introduced each other to their families. Instead, they cut out each Christmas for a tropical vacation, telling the folks they're off to help starving children in Burma. As Brad says, "You can't spell 'families' without 'lies.' "

This year their flight is canceled and a news camera puts the couple on TV, so there's no escape: It's off to see mom and dad and mom and dad, each divorced and living in his or her own special pit of middle-class misery. Brad's pop (Robert Duvall) is a meathead whose other two sons (Jon Favreau and Tim McGraw) are cage-fighting morons. Kate's mom (Mary Steenburgen) is a cougar whose new boyfriend (Dwight Yoakam) is a rock-and-roll pastor. Brad's mom (Sissy Spacek) is a hippie married to his childhood best friend.

Kate's dad (Jon Voight) is surprisingly normal. There's always one freak.

Filling out the roster is a gaggle of relatives (Kristin Chenoweth, Carol Kane) and truly hateful grandchildren. It's tough to decide what's more depressing: watching some of the finest actors of the 1970s pick up loose change playing these cartoons or the sight of director Seth Gordon (who made the excellent 2007 videogame documentary, "The King of Kong") taking on a cookie-cutter comedy and losing.

At least the leads are interestingly mismatched: Witherspoon's pointy-chinned delicacy and Vaughn's blubbery sarcasm go together like after-dinner mints and beer. They're both whip-smart actors, though, and you can see them looking desperately for a way to crank "Four Christmases" into a good, rude farce. The scenes that simply let the two fire wisecracks off each other are funny yet intimate, and there's comedy even in the way Vaughn towers over Witherspoon, an unwashed Great Dane to her crisp, yappy terrier. They belong in a movie together. Just not this one.

Anyway, like all lousy home-for-the-holidays comedies, "Four Christmases" doesn't even have the courage of its own bile, ending with a message of love and fuzzy fellow feeling that directly contradicts the misanthropic sourness of everything that has come before. When will filmmakers learn that if you start with "Bad Santa" and finish with "It's a Wonderful Life," you just end up with curdled eggnog?

Ty Burr can be reached at tburr@globe.com. For more on movies, go to boston.com/ movienation.