Mouse fun
Reminds me of the time when I was working in a studio on Mac II's.
I hooked up a spare mouse up to a colleague's spare ADB port and removed the track ball. Over the next couple of weeks, I drove him absolutely wild by occasionally sticking my finger in the carefully hidden mouse and giving one of the rollers a little spin to send his pointer up or down the screen. Not helpful when you're trying to use Adobe Illustrator.
Needless to say he went absolutely MENTAL when he found out. Fun times...