Continuity mistake: Tara is sitting at her desk and tells Max they will have sex the following night, and she teases him that she "Might even bring some props." Right as she says this line, the camera cuts. In the first shot, she has one pencil in each hand, but in the second shot, suddenly both pencils are in her left hand. The position of her hands changes between cuts as well.
Continuity mistake: When Marshall and Jason are speaking in the hallway near the end of the episode, watch the background. The extras playing the students often do not match as the shots cut back and forth. (Most obvious being that students walking down the hallway, who vanish and appear when they should not).