Not only is Dasher one of Santa's reindeer, but it's also a very exciting text-input project out of Cambridge University.
Dasher has been around for several years - I did a presentation on it back in grad school, and version 4 is now available for download.
It is completely different from anything you've experienced before. I hated it before I really sat down and used it. It's fast, it's fluid, and it's fun.
They describe it better than I can...
"Dasher is a truly innovative free software package that allows the user to write efficiently, without a keyboard, by simple steering gestures. Writing hello with Dasher Steering with an ordinary mouse, beginners can write at 25 words per minute after an hour of practice. Dasher can be used equally easily with touchscreens, head-mice, or eyetrackers. It's useful for people with special needs, for children, and for anyone who wants an alternative to a keyboard. With Dasher, you can write in almost any language. Dasher is available for all the major personal computer platforms: GNU/Linux, Windows, and MacOS-X. It's free software, and will always be free.
Dasher is fast, efficient, easy to learn, and fun to use.
To try it out, visit www.inference.phy.cam.ac.uk/dasher/. Read the tips for beginners, download Dasher, and steer away!"
Here is an image to give you an idea of what makes Dasher different:
Visit their website at: www.inference.phy.cam.ac.uk/dasher/