Speaking of painting and computers, I've been working off and on on "JokerPaint," a little let's-beat-images-senseless sort of toy made using Processing and with a lot of the heavy pixel lifting being done via chains of filters that I've made using the GLSL framework in Andrés Colubri's GLGraphics library. I expect that at some point I'll post it to OpenProcessing.
The image above was generated from the photo in this recent post. Unlike most paint-like image processes, JokerPaint's imaging is continuous and real-time -- never static. It's constantly revising and touching-up and I just picked a frame at random for this still picture.