processing.org Processing is a flexible software sketchbook and a language for learning how to code within the context of the visual arts. Since 2001, Processing has promoted software literacy within the visual arts and visual literacy within technology. Students, artists, designers, researchers, and hobbyists use Processing for learning and prototyping.
openprocessing.org Creative coding, experimental designs, digital brush painting, dynamic games, particle systems
tinkersynth.com Tinkersynth is an experimental art project. youtube.com/watch?v=od1B1Z7rrJc It lets you create unique generative art by making serendipitous discoveries through experimentation.