greasemonkey

I know that I have been slow to get to this one, but greasemonkey is just plain cool.

"Greasemonkey is a Firefox extension which lets you to add bits of DHTML ('user scripts') to any web page to change its behavior. In much the same way that user CSS lets you take control of a web page's style, user scripts let you easily control any aspect of a web page's design or interaction."

Basically, hack the UI of any or all websites that you surf.

Tags: ajax greasemonkey