Hi,
codeswarm.rb is a rewrite of Michael Ogawa's code_swarm in ruby using cairo.
For an example see: http://www.youtube.com/watch?v=PxjLbj8oT1k
For the original code: http://code.google.com/p/codeswarm
The format of the events xml file is compatible with code_swarm's one, and the physics engine is basically the same.
The code is less than 500 lines of code, so it should be fairly hackable.
http://github.com/felipec/codeswarm.rb
Enjoy :)
-- Felipe Contreras