Awesome!
For Quadrant
I'm using the Quadrant to control a synthesizer written in Pure Data. It allows you to play much more expressively, especially if you don't have a velocity sensitive keyboard. There are so many more things I have yet to try out (send midi to hardware synthesizers, play around with gestures, create entire instruments based on it, place it under a plant and capture its movement, mix quadrophonic audio, ...).
There are example Python scripts that help you get started. Basically you get four values from the board representing the proximity of an object to the sensors. You can do whatever you like with these values: Calculate the angle, measure the acceleration, recognize swipe gestures, ...
The sensors are pretty fast and precise, too.
If you have some Python skills you can easily expand the example scripts. Of course you can also use any other language or tool of your choice that reads serial data. Even if you don't program, you can just run a script that sends the sensor values to Pure Data or via midi and handle the rest from there.
The quadrant is a great device. I hope more people will pick one up, I'm curious what they'll come up with.
