Years back, I was doing tech support, and was also a massive fan of the open source remote desktop system, VNC.
I worked in a University computer lab. We have about 50 PCs, and 1 Power PC based Mac.
My boss managed both staff and student support, and his office was a couple of floors down. I was (and am still) friends with the technicians who did staff supoprt, and they were based in his office.
One day, we were going to lunch, and my friend came up with an idea. He asked me to install the VNC server on the Mac, put an out of order sign on it (to prevent the students using it), turn the monitor off and give him the IP. He also asked me to disable power saving.
Then, when our boss went for lunch, he leapt on the boss's PC, installed the client, connected it to the Mac, and made it full screen.
When the boss came back, he was rather confused to find that his Windows NT 4 desktop had apparently been replaced with a desktop he didn't recognise (he was one of these people who viewed Macs as a a waste of time, so never bothered to use one).