Continuity mistake: When Dana kicks the trashcan off the stage, we get a quick shot of it traveling toward Yolanda. But the path it travels would hit her in the face, yet it smacks her squarely in the side of the head.
Continuity mistake: In the scene where the drama teacher is in the copy shop trying to decide what color paper to buy, his hand keeps moving between shots. Every time the shot is from the copy shop side of the counter, the drama teacher's right hand is in front of the blue paper. But every time the shot is from the drama teacher's side of the counter, his right hand is in front of the orange paper.