Continuity mistake: Mama says that Curly must have gotten into some of her leftover pasta fagioli, but that wasn't among the things she ordered the night before at the restaurant.
Continuity mistake: In the dock scene where Rob Schneider kicks David Spade in the groin the first time for supposedly sleeping with his daughter, his good foot has a black shoe on it. Then as you see him kicking Daid Spade he has no shoe but is in bare feet, But when he falls down from the pain in his bad foot you can see that he now has a black shoe on his good foot again.
Continuity mistake: The lifeguard's pants at the pool are first black, then dark green, and then in the next scene black again.
Continuity mistake: In the scene at the water park, the ladies are looking at the Canadian. In the background there is a yellow towel on a chair. But between the shots, it changes to a blue towel and then back to a yellow.
Visible crew/equipment: When David Spade is telling the others about his naughty dream and we see Rob Schneider's hot daughter in the background (leading everyone to believe that it was she that he was talking about), a boom mic can be seen at the top of the screen (when the camera is facing the lake).
Factual error: The championship game was in 1978. Thirty years later, in 2008, the coach dies. Lenny rents the lake house for the three-day Fourth-of-July weekend. In 2008, the fourth of July fell on a Friday, not on a Monday as depicted in the movie.
Factual error: Adam Sandler is cooking bacon on the bug zapper, laying the meat on the outside cage. That couldn't happen, since the outside of a bug zapper is not hot and has a covered protection cage to avoid shock. (The cage is what the bacon was lying on.)