Scare your friends, coworkers or parents!
Secretly run this free and harmless prank program on your “victim’s” computer and do not use the mouse after running because mouse movement is the activator for this computer monitor prank. When your victim starts using the computer by moving his/her mouse, he/she will see strange monitor interferences after a while. :) The software is easily installable / uninstallable and absolute harmless.
Hint: You can create an Autostart Shortcut too, if you want.