This is the instrument that the Grizzly Bear man was using in Jed's resent post. Its called the Omnichord and was introduced in the early 80's by Suzuki. One uses the omnichord by strumming the touch plate and holding down chord buttons as demonstrated in the video.
Jed, if you like the idea that Bjork is in the sound booth helping the Grizzly man, don't watch the video. To some, the video might cause some disenchantment due to the simplicity of the action. I, however, think that using a musical machine like this, in any capacity, is brilliance. It is a perfect example of what happens when you mix music, magic, and technology.
The fun stuff is about a minute in.