Over the course of 80 minutes, the disappointing comedy "Four Christmases" hauls out countless stereotypes and attempts to play them for kicks: There's the cougar, the camouflage-wearing redneck and his wife -- a woman with a penchant for cooking with Miracle Whip and E-Z Cheese. Then there's the Neil Diamond doppelganger who just so happens to be the pastor at a charismatic Christian church.

But the action centers on the emblematic 21st-century couple: Brad (Vince Vaughn) and Kate (Reese Witherspoon), an affluent San Francisco pair who profess to want neither children nor marriage. They prefer the footloose lifestyle of late nights and interesting couple activities, like dance lessons.

Of course, Brad and Kate don't care for their families -- from Kate's cougar mom to Brad's redneck dad and everyone in between. Both come from broken homes. Their plan of avoidance includes booking a vacation every Christmas -- this year they're destined for Fiji. But when a dense Dec. 25 fog tips into the Bay, their flight is canceled and they're forced to spend the holiday visiting their splintered families. Enter the magic of Christmas.

To be sure, the movie has a few hilarious moments: In the very beginning, an amusing scene shows the couple indulging a devious role-playing fantasy. Later on, Brad gets the acting bug when he's drafted to play Joseph in the church's holiday pageant. By the end of the play he is so overcome by a performance high that he starts barking ad-libbed orders at a panicked and stage-frightened Mary -- who, of course, is played by his sweetie Kate.

"Four Christmases" is also a nice-looking, watchable movie: The performances are strong, even if the chemistry between Vaughn and Witherspoon is lacking. There are plenty of stylish clothes and rich, character-driven set designs -- frilly interiors at the "cougar's den," taxidermy at the redneck's house. The soundtrack is made of catchy, fun-loving Christmas tunes. (The film was directed by relative newcomer Seth Gordon.)

But the script is only marginally comical. The jokes are lame and, for the most part, overly reliant on cliché. (Matt Allen and Caleb Wilson are responsible for the second-rate screenplay.) Worst of all, the story's central conflict isn't even believable: The couple start Christmas Day on the same page. But as they circuit their family's various functions, Kate becomes racked by maternal longings. At her mother's house, she holds an infant niece who's plagued by projectile vomit, and voilà -- suddenly she, too, wants to spawn.

Needless to say, this doesn't go over with Brad. Soon the bickering between him and Kate is so intense the moviegoer is reminded of Edward Albee's insufferable "Who's Afraid of Virginia Woolf?"

In the end, a musty procreation moral is left to push forth this flimsy plot -- and that's neither original nor particularly funny.