One of my goals this summer is to learn the programming language Processing. So a good portion of my time so far this summer has been spent on learning the ins and outs of the language. (In case you want to know it is sort of like a combination of C+, and the statistical programming language of R.)
Anyways, PaintDrop is the first program that I really like that I have done. It generates pictures like the one above. You can check it out here. (While running the program you can click on the picture to have it start making a new one.) Rock on.