"Buzz is the first ever "easy to use" free modular software based synthesizer. What this means is that the entire system is based on objects, which may be routed in a modular fashion, giving you the freedom to be as creative as you want. For example, if you wish to run 3 Physical Modelling synths and a Drum Machine through 2 seperate Stereo Delays, into a Mixer, through a Compressor and Parameteric EQ, and finally out to your speakers - no problem. Lay down your synths, connect the wires and you're done." - www.buzzmachines.com
I saw a video on Youtube of a guy playing with a monome 40h and a program he wrote called 7up that interfaces with Jeskola Buzz.
I just downloaded and played with Buzz briefly and already I'm getting excited.