Make and originally thought it was probably about keyboard size, but in fact its almost a meter across.
It was originally used to create music which in turn is analyzed by a computer to project evolving images of 3D worlds on on a screen in front of the performer. Have a look at the video at http://arboration.com/ to see what I mean.
Once I realized the size I started to imagine how it could be used for live musical performances, for example by a singer to control a computer synthesizer.
Images of Kraftwerk and their drum pads, and Jon Anderson, formerly of yes, playing bass pedals by hand during "Starship Trooper" came straight to mind. Could Linkin Park use it to trigger the synth sounds at the start of "Numb"?
The website shows that the pads are just connected directly to an Arduino, but doesn't give any details of the circuit or software, but it could be fun