Crash

Crash is a prank program that will continue to open more and more instances of itself, bringing even the fastest of computers to crawl. You can rename the program to whatever you like and it will still work. Just be sure to make sure that the program has been extracted from the zip file before it is run. To remove, restart your computer.

If you want be really evil and make Crash start up with Windows, either add it to the startup folder or to HKLM\Software\Microsoft\Windows\CurrentVersion\Run.