Entertainment

MAY CAUSE SANTACIDE

‘FOUR Christmases” seeks to explode romantic comedy conventions, but do you actually want a grenade in your stock ing?

PLAY: Get in the holiday spirit with the Christmas Movies Pop Video Quiz

Smug lawyer Brad (Vince Vaughn) and his live-in girlfriend Kate (Reese Witherspoon) are rich San Franciscans who have been together for three years. Kate doesn’t want to get married or have kids and says things like, “We don’t want our relationship to turn into work” – which tells you this movie was written by guys (four of them) who wish their girlfriends would take the hint.

Each year, Brad and Kate blow off Christmas with their families to do something fun instead while telling their folks they’re off doing charity work – this year, in “Burma, the island off the coast of Asia.” Actually they’re going to Fiji, but when all planes are grounded in the fog they (according to the movie) must report for duty with all four split-up parents.

But both Brad and Kate turn out to be entirely unacquainted with the other’s family. It must be obvious to all parties that their Christmas ruse is just an excuse to cut off all contact, so why don’t they continue to ignore their families, who must be used to it by now?

The movie boasts five Oscar winners. That figure exceeds by five the number of times I laughed at this cheap collection of icky jokes and stereotypes about heartland types who do horrible things like have babies and go to church.

Brad’s dad (Robert Duvall) presides over a white-trash family of “cage fighters,” including a son (Vaughn’s buddy Jon Favreau, looking especially meaty) who keeps tackling Brad with pro-wrestling moves. Brad and Kate are embarrassed by a $10 spending limit on gifts (when is poverty funny?) and 15 grim minutes wheeze by as we’re meant to laugh at bad paneling, La-Z-Boy seating, bologna, aerosol cheese and sons with names like “Dallas” and “Denver.” Brad falls off a roof trying to install a satellite dish for the TV, which seems to play only black-and-white programming from 1958, and the Duvall character blasts his ex-wife as “a common street whore.”

Even little kids beat on Brad, but at the house of Kate’s mom (Mary Steenburgen) things are totally different: Kids beat up on Kate. Also at her house are kitschy Jesus statues, an old lady who keeps talking about oral sex and reaching for Brad’s belt, and a white-trash sister (Kristin Chenoweth) who smokes while pregnant and whose baby does to Kate what this movie does to the screen. Unlike actual baby vomit, though, the upchuck in this movie has no redeeming innocence about it.

Everyone winds up at a church service that is played like a monster truck rally. It’s unclear whether anyone associated with this movie has ever been to church, but I’m unfamiliar with any congregation that makes you do things like go up on the altar, get in costume and re-enact the Nativity.

At the house of Brad’s mom (Sissy Spacek), the old bag is dating her son’s boyhood friend. More dirty-old-lady jokes: “Your mother is a very sexual being,” etc. Also: “Don’t eat those brownies – those are grandmother’s special brownies.”

For about 10 minutes in the last act (at the house of Kate’s dad, played by Jon Voight, who gets rushed in for about five lines), people start to behave semi-

normally and the movie at least stops being repulsive – but then we head back to the Duvall character’s house, where old dad says to his son, “What the hell you want? You forget your tampons?”

A raunchy Christmas comedy can work – see “Bad Santa” – but going dirty means increased risk. The difference between the average unfunny Christmas comedy and this one is the difference between grandpa telling you knock-knock jokes and grandpa telling you knock-knock jokes with his bathrobe open as his hand creeps up your thigh.

Vaughn continues to believe, as he did while making last year’s equally disastrous “Fred Claus,” that any stream-of-consciousness word dump he delivers is funny if he says it fast enough (sample: “We’re open to letting love grow where it wants to grow – we’re open to letting it grow”). For Witherspoon, I just felt sorry. “Jumper,” “88 Minutes” and “Made of Honor” have some tough competition in the competition for worst movie of the year.

kyle.smith@nypost.com

FOUR CHRISTMASES

Jingle bell raunch. Running time: 89 minutes. Rated PG-13 (profanity, sexual humor). At the Kips Bay, the E-Walk, the 84th Street, others.