Any Given Sunday (1999) - 5 major mistakes

Continuity: Of the people in the stands, almost every other one is a piece of cardboard with a picture on it and a balloon in their hand.

Factual error: In the final game of the movie, when LT gets hurt making the big stop, the referee's measure for the first down before anybody attends to LT.  LT is nowhere to be seen when the measurement is made yet he was supposedly knocked out at the point of contact - where the ball should be. No way would they measure until the injured player is taken off the field and the pile up cleared.

Continuity: In the final game (at Texas Stadium in Irving) there are several low angle shots that show the hole in the stadium roof. Throughout the course of the game, the shots show a night sky, then a day sky and back to a night sky, all within the same game.

Visible crew/equipment: In the opening scene, Dennis Quaid is shown yelling out the count to his team-mates from the QB position.  His shiny helmet clearly shows the camera crew filming him as he faces forward.

Continuity: Towards the end of the movie when the long touchdown is made and then flag is thrown you see Willie running up to the referee with his helmet off, when they show the scene from a different angle his helmet is on.