"Four Christmases" hurls towering Vince Vaughn at tiny Reese Witherspoon and a lot of Oscars at a lightweight holiday farce. This comedy about a happy couple made miserable by having to visit four divorced parents begins with a bang but settles into sentiment so maudlin that even this cast can't save it.

Brad (Vaughn) and Kate (Witherspoon) are happily unmarrieds in San Francisco who fib to family every holiday season, making up stories about "inoculating babies in Burma" so that no one can gripe when they skip Christmas dinner. They'd rather fly to Fiji.

"You really can't spell 'families' without the lies," brags Brad.

But Frisco fog closes the airport and a TV reporter busts them with their ruined travel plans. Before you can say "mistletoe" (their "safety word"), they've been outed and they're driving all over "celebrating" with relatives they avoid.

Ex-documentary director Seth Gordon ("The King of Kong") stages each visit as an episode, with the energy flagging steadily from the first to the last. We meet the resentful farmer (Robert Duvall) who raised Brad to disdain family, and the brothers "Denver" (Jon Favreau) and "Dallas" (Tim McGraw) and learn that, since Dad named his boys after the town where they were conceived, Brad's real name is where Disney World resides.

Brad faces old humiliations, and Kate, on meeting Denver's always-breeding/country cookin' wife (Katy Mixon, a stitch), frets over motherhood.

Then they go visit her born-again mom (Mary Steenburgen), where Kate's competitive sister (Kristin Chenoweth, funny as always) revisits the days when "Katy Cooty" was fat.

By the time they reach Brad's hippie mom (Sissy Spacek), who has taken up with his high school buddy, the relationship and the movie are in trouble.

It's weird to watch Vaughn try to replicate the immortality his pal Peter Billingsley achieved in "A Christmas Story." First "Fred Claus," now this. Billingsley, the once-and-always Ralphie, has a cameo and got a producing credit here.

Witherspoon amps up her game to match the pace of Vaughn's manic patter. But they waste so much talent — Duvall, Witherspoon, Steenburgen, Spacek and Jon Voight (as Kate's dad) all have Oscars.

A lot of us can identify with the "Four Christmases" divorced-parents situation.

It has enough big laughs to make it marginally better than last year's "This Christmas."

But Vince, you are never, ever going to get Ralphie's Red Ryder BB gun. Give it up.