Unfreeze System with the Magic SysRq Keys

If you Linux system has ever frozen up and CTRL, ALT + BACKSPACE does nothing and you feel tempted to hit the power button (which isn't advisable as the Linux kernal could still be written to). Do the following instead:

1. Hold down the Alt and SysRq (Print Screen) keys.
2. While holding those down, type the following in order. Nothing will appear to happen until the last letter is pressed: REISUB
3. Watch your computer reboot magically.