Replying to Awesome Prank Oppertunity - Help needed

So in my archatecture class, everyone is on a computer and i had to switch computers. I logged on and found out that my new computer has the teacher version of Syncroneyes, a program that lets teachers watch what kids are doing and control their computers, ex

I played around with it and it is so cool, i can control anyones computer. The problem is its really obvious and kids realize it instantly.

I need some good ideas to fuck with other ppls computers that they wont notice right away. Any help??