This made my day: a Javascript version of the old "Asteroids" game that lets you blow up HTML elements on web pages.
To try it out on this page, you can click this link. Rotate with left and right arrow keys, up arrow for thrust, shoot with the spacebar, press B to highlight shootable regions, and Esc to quit. (You'll probably want to reload the page afterwards.) For more fun, drag that link to your bookmarklet toolbar, then invoke it from some other webpage -- maybe one laden with ads, or maybe one with photos of whoever's pissing you off this week...
A tip of the hat to young Mr. Erik Rothoff Andersson, author of this applet.