What's the best prank you've ever been a part of?
For me, it was something my Managerial Accounting class pulled on our teacher. She was about ten 分钟 late, and everyone was getting fed up and getting ready to leave, so one of the guys set the clock ahead fifteen minutes. Our teacher didn't notice the time difference until there was about half an 小时 left of class (real time) and the clock 说 there were only fifteen 分钟 left. She asked all of us "good students" (which I happen to be one) what time it really was. All the kids that had watches and cell phones 说 the clock was right. I didn't have a watch, so I didn't have to answer at all. :)
It didn't end very happily, tho. She made us stay five 分钟 late according to her watch to make up for it, just in case. But no one ever mentioned what happened.