A while ago, I ran across the processing language/environment while examining the computational art of Jared Tarbell. I didn't really dig into the tool Tarbell was using though.
Ben Fry and Casey Reas' processing toolkit is centered around a domain specific language for doing interactive 2D and 3D graphics. The language is layered on top of Java so has a relatively portable development environment and can even be compiled into applets. As far as I can tell, there's nothing really interesting from a language design perspective, but the authors provide some comparisons with other languages.
The point of processing isn't to be radical though. Instead, the language is supposed to be quite accessible to those who aren't typical programmers. I don't know the background of all the artists that appear in the online exhibition, but whatever their hacking abilities, the works are pretty impressive. Besides Tarbell's stuff, the whizzy zipdecode application making the rounds of the blogosphere was done in processing
I've actually been thinking that a similar combination of domain language on top of Jython with prefuse inside would be really neat.