Continuity mistake: When Don Knotts is in the old Simmons mansion, he falls down a chute of some kind. If you watch closely you will see the stunt person looks nothing like Don Knotts. It is a younger man with very straight hair.
Continuity mistake: When Peter O'Toole is locked in the closet at the museum, he puts a rope through the keyhole and uses a hook to pull it under the door. In the first shot, from outside the closet, the end of the rope is to the right. In the next shot, from inside the closet, the end of the rope slides under the door to the left. (01:22:30)
Continuity mistake: As George says "That you people are rearranging my genes so that everyone will be like everyone else" he puts his left arm around Nick. His hand, though is on the back of the sofa. Instantly in the next shot, however his left hand is now on Nick's left shoulder.
Continuity mistake: When Owen looks down Bourbon Street the day after he found the snowglobe, there are no cars parked on the opposite side of the road and two women are walking on that sidewalk. He crosses the street and now a car is parked and the passersby are different. (01:32:05)
Continuity mistake: When Alfie helps a woman out with a doctor, it's raining, but when Alfie goes outside the rain has stopped and there's no water on the ground.