If you want to put your touch typing skills to the test, BlindType is your keyboard. It learns your typing patterns and then gives you the option to make the keyboard disappear—as in, there are no keys while you type.
What's crazy is that you can literally type anywhere on the screen—sideways, on top, tilted, anything—and its software engine and very impressive auto-correction figures out what you're trying to say. You can even shrink the keyboard, or turn it diagonally.
I'm not sure what practical purpose BlindType serves (maybe logging in to websites) but it's definitely a fresh take on mobile keyboards (and not to mention sorta mind-blowing). BlindType is planning to release "soon" for Android, iPhone and iPad. [BlindType via Talk Android]