movie trailer (apple.com - quicktime)
NOTE: This spoiler was sent in by Kaci.
The movie starts out with Drew (Ben Afflek) character wowing a bunch of ad execs with a promotional idea for spiked eggnog. Then it cuts to that night with his girlfriend. He presents her with two tickets to Fiji. She's disappointed because she was expecting some kind of proposal. She gets upset and starts asking questions about why she's never met his family, says that he's not serious about the relationship, and then walks out on him.
The next day, he's at work and tells his secretary to send her a gift to win her back. He realizes that he's going to be alone for Christmas so he starts calling up all the people in his address book. No one wants to have him over for Christmas.
He ends up running to the airport to catch the shrink of his girlfriend as he's trying to leave on a plane with his family. The shrink tells him to write down his grievances on a piece of paper, and then burn them at a place that reminds him of his childhood.
So he drives out to the suburbs and pulls up to a house. He gets out and starts hugging trees and saying things like "This is it!". Inside the house, the parents Mr. Valco and Mrs. Valco (James Gandolfini and Catherine O'Hara) are arguing about the son spending too much time on the computer. They see him kneeling down on the sidewalk and light something on fire. The dad walks out and hits him over the head with a shovel.
Cut to inside the house. The family is standing around wondering if he's dead. He comes to. He gets a tour of the house. They let him stay for dinner. They ask him to leave. Once outside, he turns back around and starts banging on the door. The dad opens it up and he offers to pay them $250,000 to pretend to be his family for the holidays.
A lawyer comes and they sign legal papers. He makes them go tree shopping, and the dad has to wear a Santa hat. The sister Alicia (Christina Applegate) comes home and has no intention of adopting this new brother. She demands that they kick him out.
At dinner, Drew shows up with an old man and says that he is the Grandpa. He's a local theater performer who Drew hired to fill the role. Grandpa hands out tickets to his upcoming performance of Scrooge. They all sit down and have dinner. Drew pulls out a script and gives copies to everyone and asks that they all read through the scene. Everyone gets annoyed.
They all go shopping the next day. They get a group Santa picture together. Then Mr. Valco tells Drew that he and his wife are thinking about separating and having him there is making things worse. Drew tells him to go out and buy something for himself that will make him feel better. Then he tells the wife that he's going to set up a private photo shoot and have her all dressed up. Something just for her. She's so happy she cried. At the shoot, she's dressed in leather and a ton of makeup. She seems to be having a great time.
Drew gets the son and sister to go sledding with him. The old hill is now too small so he charters a helicopter and carries them to the top of a mountain. The brother says no way. Alicia says that he never had any intention of going down in the first place. They sort of dare each other into getting on the sled. Then they go screaming down the mountain. At the end Drew and Alicia crash and start laughing. They almost kiss but Alicia sneezes.
They both get colds and spend the afternoon talking and watching TV. She tells him about a time when she was 9 and saw a tree covered in ice. It was beautiful and she always wished she could live that moment again.
He confides that he never lived in that house. His father walked out on them when he was little. His mother worked in a diner and he spent every Christmas alone.
Later on, he takes her outside. He had the tree covered in ice and flew in a bunch of dancers and singers. There are lights and music and statues. It's all very gaudy. She gets offended because it's so over the top.
Meanwhile, the girlfriend is talking with her parents. She got the gift (a diamond bracelet) that his secretary sent her, and she wants to make up. She calls and says that she wants to meet his family. She tracks down where he's staying and shows up at the house.
Drew had just told the family that he was leaving. But now he is forced to offer more money to have them pretend to be his family in front of his girlfriend, and her parents.
The old man playing Grandpa couldn't show up, so his understudy comes over. He doesn't fit in as well with the family and everyone is starting to ask questions. Alicia comes home and apologizes to Drew. She kisses him. As soon as she leaves, his (ex) girlfriend walks in and they end up kissing too. Alicia sees him.
She decides to get even. She plays along with the family, making cutting remarks and finally causes Drew to lose it. He rants about how they were just making out in the kitchen. Then he tried to cover by saying they're a very affectionate family.
Meanwhile the son is upstairs. "Grandpa" had come in while he was looking at porn and they found a website that was posting the pictures that Mrs. Valco had gotten taken. She didn't know they were being posted in that way, of course, but the son is frozen in shock. The whole family (girlfriend and her parents included) come walking in and see the screen. Everyone freaks out. The parents of the girlfriend finally say that they've seen enough and they all storm out. Then Mr. Valco storms out saying he's staying at a hotel.
Drew goes back home to his huge empty apartment. Mr. Valco shows up. Drew stills owes them money. Drew writes a check and then they talk about how Mr. Valco wishes that he didn't separate from his wife. Drew mentions that he still has the ticket to the performance of Scrooge. They go, not knowing if his family will be there. They are. Mr. Valco and Mrs. Valco make up.
Drew hooks the brother up with a cute girl in the audience. When he goes outside, he finds Alicia. They kiss and make up. The ex and her parents drive by and witness it, in all it's open mouthed glory.
They speed away into the night.