On the night the kids go to Mrs. Tingle's home, Mrs. Tingle's robe opens and closes repeatedly between shots.
When Leigh Ann and Mrs. Tingle fight towards the end of the movie, the blood running from Leigh Ann's nose keeps changing patterns. It starts off as a big blood smear to a simple line of blood running down her nose.
When we first see the principal of the school standing on the front steps of the school, he has a coffee mug in his right hand. He moves the mug to his left hand but after a cut, the mug has jumped back into his right hand.
When Mrs. Tingle first walks down the hall and kids try to get out of her way, two students dodge her twice. A fat white girl and a black girl wearing a blue dress separate from each other twice. The second time you see them split, the black girl screams as she moves.
No accused witch was burned at Salem. The victims of the scare were all hanged. Therefore Leigh Ann's report is flawed and Mrs. Tingle is entitled to mark her down on it.
When Trudy is "shot", the arrow hits the grade book she's holding. Some thought they saw blood where there should be none, but that is the red tail of the arrow.
When Leigh Ann and Luke are having sex, Mrs. Tingle tries to break free of her constraints. In the close up it is clearly noticeable that there are two different sets of constraints that are not attached in any way, one around Mrs. Tingle's wrists and one around the bed post. The one around the bed post has a loop for Helen Mirren to put her wrists through. The constraints would go back with Helen Mirren's wrist if it were a single piece, but the loop keeps its shape.
When Luke is feeding Mrs. Tingle the burger and fries and she asks for some wine, the second time he brings the cup up to her lips for a drink, she leans down to take a sip but you can clearly see she doesn't take a drink at all.
When Katie Holms is changing her grades, while concealed under a blanket after having sex, a bra strap is briefly visible.