This is a simple IT Gag which I have never seen anyone else do before. I like to think I invented it! I can assure you that it is easy, fast, and really obnoxious.
- Take a PRINT SCREEN of you buddies desktop
- Save it as a .JPG
- Set that .JPG as the wallpaper.
The victim will not likely notice this for some time, which makes it all the better. This will drive him nuts as he tries to move files stored on the Desktop it will appear that he is making copies. Very annoying.
Its the simple things in life that give the greatest pleasure.