There's a great video making the rounds in the Linux community.
One of the most famous (or infamous) commands in the NIX world is running rm -rf / as a superuser.
For those of you who aren't fans of Unix or Linux, this command basically tells the system to remove all files and directories starting at the root directory and not ask for any confirmation.
Ever wonder what would happen if some fool actually did run it?
Enter the Fool. Check out this video and watch Linux magically disappear: