When Cynthia jumps in the bay after the ladies meet Salvadore on the east side, she is clearly wearing a blue bikini outfit. When she comes out of the water, her outfit is now pink and remains pink throughout.
During the first morning scene on the beach the sweat on Vince Vaughn's shirt changes between shots.
In the beach scene (where they take their clothes off), Cynthia takes her shoes off before walking out to the beach, then we see her with her shoes on the beach.
When Dave and Sctanley are talking just before they play Guitar Hero: World Tour (2008), Dave's guitar strap is straight. He looks away, then it is twisted, and then it's straight again.
When we first see Jason sitting behind the desk talking on the telephone, the time on his wristwatch alternates between 11:35 and 12:10 several times.
When Shane is over at Eden East trying to find Trudy, he is telling his ex-wife "I got a lot of friends because, I'm the way I am", but his mouth is not moving.
On the first night when everyone is sitting down at the restaurant for dinner, Cynthia's line is "Did you guys hear what they have at the spa with the snow?" but her mouth is not moving.
When Grandpa Jim Jim starts his big American car at the airport, the sound is of a small Japanese car. This scene is not on the DVD release.
At the beginning of the movie, Vince Vaughn's character is working on the launch of Guitar Hero, which is one of the reasons he can't go on the trip the following week. How is it that Sctanley has the game and has become an expert at it already, if it hasn't launched yet?
Both Kristin Davis and Malin Akerman break character in the group yoga scene, and are laughing hysterically and trying to hide it.