Saw this on lifehacker.com:

“Basically, once your typing speed passes a certain threshold (the default is 40wpm, but you can change it), every window but the one you’re typing in fades to black — the point being that once you hit a certain typing speed, JediWPMConcentrate acts as a sort of “bloodlust” mode for your typing and focus. Once you drop below the typing threshold, the background fades back to normal.”

[click here for download link]

Freaking cool, idn’it?