The word "Sender" written on the blackboard changes frequently.
When the Stupids set off to Warehouse 21, they leave when the sun is up. Their car passes under a bridge with a sign reading "Warehouse 21 5 Miles," but when they arrive at the warehouse, it is the dead of night.
The garbage truck stops only for the Stupids' garbage can and ignores the others.
When Stanley puts the key in the glove box, it is a small key chain. After they switch places and Joan turns the key in the glove box, it is a larger key chain.
When the crossbow is shot at the Stupids, the cable or string used for the effect can be seen in front of Buster before and after the arrow lands into the pole.
When Mrs. Stupid jumps into the elevator at the museum, a large corner of the green safety mat she jumps onto can be seen.