With some mice you can go into the properties and complety invert it s left goes right up goes down etc and make it lefthanded so a left click opens up properties boxes instead of selcting.
Get a fake virus file and put it in their startup menu so every time someone boots up the comp it says its erasing windows.
Change the properties of their My Documents and any other files/folders on their desktop so that they are hidden files then make sure that viewing hidden files and folders is turned off in windows. They won't be able to find ANY of their stuff when they log on.
Black shoe polish on the phone receiver works nicely.
Remove all the screws from their chair leaving only 1 in just enough to keep it together until they sit down. (see Jackass reruns for example)
If they're really computer illiterate and you are on a network use netsend to send them "Big Brother is watching you" messages and tell them to stop screwing around on porn sites and get to work. I do this at work to new people and they always freak out thinking they're being watched.
Go into Word and go to format then font and change the font to wingdings then hit the default button at the bottom and every document they open after than will have the default font of wingdings.
Get some extremly hot hot sauce or even some hot peppers and run them on the lip of the targets coffee cup.
'00 Blk CSVT #1087/2150 built 12/23/99
