Heheh. I had an 8am lit course one semester where it was all of 10 people and a grad student as the instructor/TA (let's call him "J."). Since it was so small, we got shoved into this one room with only a medium sized table, and this room was in one of the buildings open 24 hours. It wasn't too rare to find people taking up one of these rooms to study in the evenings and sometimes, early hours. One morning, the TA showed up to class and found some guy still in the room who fell asleep studying for an econ test, papers and everything spread all over the table. It happend that the next guy who showed up for class was the TA ("R.") for the guy sleeping ("M.") so he knew exactly what the material was, how the professor administered exams, etc. so the J and R hatched a plan:
R quietly went into the room, threw some writing on the board like "5 minutes left", "correction on question #17: label should be xxxx", etc. while J stood outside and waited for everyone to show up, then handed out copies of an old econ problem set that R had with him. Once everyone arrived, we snuck into the room without waking M, spread our papers like there was an exam, and put one of the problem sets in front of M. Then on cue, R loudly announced "Time's up, hand in your papers" and everyone did the traditional 'write down something fast' routine. Just as planned, M shot up, looked around in desparation since he saw everyone writing stuff down, handing stuff in, and here he had nothing on his paper.
Yeah, he caught on after a full minute, but the look on his face was priceless. 😀