Continuity mistake: When Turk is talking to someone about the teenager getting breast implants, in the first shot you can see he is talking to someone in a a blue shirt with a stethoscope - i.e. JD. However after this shot, JD has vanished and the conversation is suddenly with Todd.
Continuity mistake: When Turk and Elliott are in the line at the cafeteria, you can see that Turk has two plates on his tray and Elliott has a juice box on her tray. When they turn around at the end of the line Turk has just one plate on his tray and the juice box on Elliott's tray is also gone.
Continuity mistake: When JD's Dad arrives at the apartment, and sits down to drink a beer, from straight on his jacket is open and his tie is draped to the right. When the shot cuts to a view from the side, his jacket is now open much less, and the tie hangs straight down his shirt.