I TA'd a CS class a little while back that had a pretty neat online grading system. You submitted your code and it graded it, posting the results to a scoreboard so you could see how you were doing vs. the rest of the class. Of course, the scoreboard used nicknames so you couldn't actually tell who anyone was.
One student decided it would be funny to call himself "Cunt Destroyer". I'm not sure if he didn't realize that just because he was anonymized on the scoreboard didn't mean we couldn't look up who was using that nickname or what, but it didn't go over too well with the course staff (though we all got a good chuckle out of it).