Over the summer I took the Kadenze Machine Learning for Artists and Musicians online course.  It was very informative and then often used these weird Gametrak golf game controllers.  While it looks like there are just two joysticks on the device, there is also a neat z axis wire that you can pull out of the joystick.  So there are really 3 axises of control, one of which has a bit of tangible resistance response built in.  I was able to pick up a used one on the cheap and hacked it into this weird audio visual machine.  It uses a web camera and overlays a series of effects while playing a scrumbly FM synth.  I actually found it easier to map this without using machine learning :-/.