For his first master's project, Kennon Ballou created a web-based, collaborative genetic art program that generated abstract images based on a tree-structure genome. A current working version is here: http://www.magnetdust.com/collabGenArt/images.php
(Please don't spread that link around; my server would die a horrible, flaming death)
Collaborative Genetic Art PHP Source
A directory with images generated by this system can be found here: http://www.pleonast.com/kennon/art