I found this yesterday on the Google Chrome Store and I'm already loving it.

Nitro Type | Competitive Typing Game | Race Your Friends

Simplest explanation; You compete in real time with 4 other users in typing a segment of text. The faster you type, the faster your car moves on screen.

This is fiendishly addictive, I havent been able to put it down yet(mind you its only day 2..)