The Spooky Box is a simple interface for Processing that consists of 3 knobs and 4 buttons. There are two versions, an Arduino based hardware one which doesn’t exist yet, and a software emulator which I just finished. There’s also an accompanying Processing library that works for both which is ridiculously easy to use.
If you’re looking for a simple, generic UI for your Processing apps, consider trying this out. I’ll be releasing more info as the hardware gets put together.
PS. The skull image in the background there is CC licensed, and can be found here.