The background image deserves a quick explanation - it was created using the "flame" effect in GIMP, the GNU Image Manipulation Program (it's free and highly recommended as an alternative to Photoshop).
Flame starts you off with a random image, and then generates eight slight variations on the theme. You can choose one of the variations and then repeat the process, in effect "evolving" an image. The background I'm using is one that ended up being a pleasingly organic variation on a bubble chamber photo.
For a more directed version of evolved images, and to spectacular result, check out Roger Alsing's blog.