At a PC sales and repair shop I used to work at, some of us in the sales office (who were really just the techs who could actually be counted on to talk to other humans) would play pranks on each other pretty frequently. Some examples:
I'm sitting at my desk one day, with my back to one of my compatriots desks, when behind me he calls out "Hmmm...that's strange." I turn around, and his entire screen says "STRANGE." Before it can register with me just what he has done, he clicks, sending the powerpoint presentation on to "ODD" and says, "a bit odd, don't you think?" Click. "Truly bizarre." BIZARRE.

He later made a presentation complete with flow charts that showed the organization of a Bond-like cabal of customers that was trying to overthrow one of the other sales guys. Since one of our regular customers looked EXACTLY like Hitler, complete with mustache, and one walked with a limp and had a German name, and several had other foreign accents, it was pretty eerie.
Some of the guys got in the habit of disconnecting one thing or another - hard drive, memory, etc - in another's sales PC. Usually quick to figure out, just a little pain in the rump. But one day, one tech ended up completely disassembling his system, and could not figure out what on earth was wrong with it. Wouldn't power up. He even changed power supplies. Took three hours, and wasted enough time that people stopped doing this at all afterwards, but I'll always remember how frustrated he was when we showed him the little piece of scotch tape on one prong of his power cable. Which he never changed - after all, how often does one of those go bad?
![Devious :] :]](http://www.enworld.org/forum/images/smilies/devious.png)
But he had even taken it out at one point to look for scorching, and missed it.
I made a wallpaper for one of the other guys machines that was the same as the wallpaper he had before, but with an icon added to the wallpaper that said "Click Me." Which of course did nothing - it was part of the wallpaper. He figured it out shortly. A few weeks later, another icon on his desktop said "Click Me." But he tried changing wallpaper, and nothing happened - still there. So, confident it was just some little prankish thing he was missing, he double clicked it to see what it would or wouldn't do. His screen went blank, then "Formatting C: Drive - Please Wait" accompanied by very convincing hard drive activity. He tried to Cntrl-Alt-Delete - nada. I had created two little batch files that read the lyrics to my favorite song over and over, one then the other, and prefaced it with a nice little CTTY command to lock out the keyboard. He about had a coronary. But he was the one who had put the scotch tape on the other guys machine, so don't feel
too bad for him.
And then, of course, was the time that Henry (yes, Henry on this board) was teaching a class with his system hooked up to an overhead projector - but had his system shared with full access through the network. We took turns adding icons to his desktop that said different goofy stuff until he came out of the classroom demanding to know what we were doing and to please stop.
Those were the good ole days.
