I know one gunner. He was a total arse. We got him back one day, though.
He would literally it in seat #1 (labled #1), in our bio class lecture hall. Every day he'd get to class a half hour early to be able to sit in the seat with #1 on it. He tried to give people wrong answers even when they didn't ask for them, and he always talked down to people and commented on how he couldn't believe "how many stupid people think they can become doctors."
Now for the prank: the bio professor was a nice guy until we found out his absolute hatred for cell phones going off when a girl's phone went off and he stopped class, walked over to her and yelled at her in front of 500 people. So naturally, we slipped a travel alarm clock set to go off during class into his bag when he wasn't looking. So here he was during class and the alarm went off and he looked left and right to see which person next to him was the "ass". And the professor stopped and asked "What is THAT??" As he feverishly searched through his bag, in front of a dead silent (apart from the alarm clock) 500 person lecture, and pulled out the alarm clock and said in surprise, "It's... it's an alarm clock?" "WELL TURN IT OFF, NOW." So he did finally figure out how to turn it off.
Little did he know we hid a second one and this was repeated once more 15 minutes later.