Andyware has announced that Analog Box 2 is now available as an Open Source project hosted on Google Code. The license os GPL v3.
Analog Box is an open-source, circuit based, modular software synthesizer. You put sound objects on the screen, connect them together, listen and adjust. When you find something you like, you can record it to a wav file, or just save the circuit and play it again later.
ABox is somewhat like the vintage synths of the '70s in that there are separate modules with lots of patch cords, knobs, buttons and displays. But you also get the computational ability offered by modern CPUs. Features like FFTs, Differentials and Digital Control open up realms of sound design never dreamt of before.