Team 698's human player made an awesome throw across the field into our robot during our match together
http://youtu.be/OIAMnh3jYxs?t=1m57s . I'd nominate him just for that

other human players would sometimes just throw the ball onto the ground next to our bot in some of our matches, very frustrating to watch as the human player on the other side of the field.
I know it wasn't exactly a show of penalty prevention that seems to be the emphasis in this thread but it's not like he broke any rules either, just thought it was cool.
Also if you watch the whole match our robot was driving funky because of transmission problems that magically fixed themselves on the way back to the pit. Also that was one of maybe 3 shots we missed during teleop in all the qualifying matches, and we had to be responsible for every shot in nearly all of our matches.