A while back I was playing around in the GIMP, and managed to find a bug of sorts in one of the rendering plugins. By running the plugin 4 or 5 times in direct succession using the keyboard shortcuts, I was able to trip up the filter and cause corruption to the data. The output was pretty cool looking, so I fiddled a bit more and made it into a background.
The only size available is 1680x1050, but if you ask nicely I could retrofit it to whatever desktop size you would want. I'm releasing this Kopyleft, so go hog wild.