After Turk's dream of him spanking Elliot, the glove on his hand goes from having a lot of blood on it in the close up shot of Turk, to having next to no blood on it in the wide shot of the whole surgical team.
During the "99 Luftballoons" dance sequence between J.D. and the German patient, a crew members arms can be seen pushing balloons back into the shot.
The two German brothers are not German native speakers. In fact, their German is rather poor.