This is a simple bookmark that will allow you to play Asteroids on any webpage and essentially just blow stuff up! You just go to the webpage you want to play on (such as puff.com) and then use the arrows keys and space bar to promptly destroy the website! So much fun, so distracting.
Tough to describe until you do it. Check it out.
Refresh the webpage to make things normal again. Directions are on the website.