It's made in Processing. I absolutely love Processing since it makes graphics really really simple as you can draw to the screen straight away.
There's also my own "script" language in there too that some of the programs use, but it's really really bad.
I'm currently re-writing the entire thing from scratch to be a lot more modular and accessible from the scripting language. Once I have a solid base I should be able to make the rest of the UI and programs in that language, meaning components can be modified fully using the script files.