One of the rules of being an American movie watcher is you have to watch a Christmas film sometime between Thanksgiving and Christmas.This rule is largely responsible for me being able to recite a vast number of lines from Cousin Eddie, Clark and the rest of the Griswold gang in "National Lampoon's Christmas Vacation" at any time I deem them appropriate, the frequency of which increases the closer the calendar gets to Dec. 25.

Although quite a common occurrence these days (because studios know that at this time of year, we'll watch apes slap each other for 90 minutes if they're standing under mistletoe), the Christmas movie is done poorly (see any Tim Allen holiday flick) far more often than it is superbly ("It's a Wonderful Life," "Christmas Vacation").

So when "Four Christmases" came to theaters, I was skeptical, and not just because Reese Witherspoon would never form a couple with Vince Vaughn in real life. I just wasn't sure we needed a romantic comedy Christmas movie spent with four awkward families, one of which has a pair of siblings resembling the Bushwhack Brothers (Jon Favreau and Tim McGraw) who practice their moves on the green shag carpet of the living room.

"Four Christmases" is far better than I had anticipated. It's no classic by any means and occasionally crosses the line between hilarity and stupidity, but it's definitely not as bad as I anticipated.

Vaughn and Witherspoon are Brad and Kate, a couple who does their own thing without feeling burdened by the need to do what society tells them to, such as spend the holidays with family. 'Why even attempt to go through with the charade?' they figure.

Until their secret holiday vacation to Fiji gets canceled because of bad weather and the local television crew interviews them on their reaction. The secret's out, and the pair are forced into spending a few hours with each of their four divorced parents, all of whom have families that would feel more than comfortable in "dysfunctional camp."

Along the way, Brad and Kate come to realize that despite the many faults of those they share bloodlines with, there might be some benefits to this whole "family" thing.

"Four Christmases" is so bursting with star power that it threatens to explode under its own weight, even if many of the stars don't shine all that brightly.

Robert Duvall shines as bright as anyone here as Brad's redneckish father, Howard, who pounds Budweisers in can cozies while the rest of his clan argues over a $10 spending cap that not everyone was informed of. This is a man who names his children based on what city they were conceived in (Brad's real name, we find out, is Orlando, and his brothers are Denver and Dallas).

Along for the ride are Sissy Spacek (Brad's mother), Mary Steenburgen (Kate's mom), Dwight Yoakam (Kate's mom's pastor boyfriend) and Jon Voight (Kate's dad). Steenburgen is memorable as the flirty Mom-type, but the rest of the big names seem to phone in their performances.

The real stars are Vaughn and Witherspoon, who play off each other convincingly, and sometimes hilariously. It's pretty familiar stuff from Vaughn, who gets plenty of chances to do the silly shtick he's done in fare like "Old School" and "Wedding Crashers." The laughs are dumb (Vaughn screaming like a school girl while Favreau contorts him like a pretzel in a variety of bizarre positions on the previously mentioned shag carpet), but they're hearty.

For Witherspoon, however, playing the controlling, spunky Kate is a shift from the sweet, ditzy stuff she's come to be known for in the "Legally Blonde" and "Sweet Home Alabama" roles, which she's sometimes been typecast into. She's not always as funny as Vaughn, but then again, getting picked on by toddlers and getting puked on by babies isn't the riot the film makes it out to be.

Short, shallow and sophomoric, "Four Christmases" is an easy viewing Christmas comedy that could have been so much worse, and so less funny. It's a low bar to hurdle, but one that shouldn't be taken for granted these days.

There's definitely a lot less fun ways to fulfill your American duty this holiday season.

Joel Sensenig is news editor of the Review Times. He's slightly disappointed in himself for not watching "Christmas Vacation" yet this holiday season.