I just got sent this link today, but it's the coolest app I've seen in a long time. I'm typing this post without touching the keyboard, using an app called Dasher. Basically you just type by pointing and zooming in a never-ending field of letters. There's prediction so the most likely choices are larger and easier to point to and stuff. Very cool.

http://www.inference.phy.cam.ac.uk/d...rSummary2.html
http://www.inference.phy.cam.ac.uk/dasher/Download.html

(Yeah, OK, I had to press Enter on the keyboard...)