I’ve written and released some software which may be of interest.
RedPill was a screen saver for Mac OS X. It resembled the green code symbols seen in the Matrix series of movies. It no longer works under new versions of OS X.
SnowSaver 2.0 was a complete rewrite of my popular screensaver which showed 3D snowflakes. Version 2 generated snowflakes algorithmically from polygons, so that no two were identical. Apple rejected it, so it is unlikely to be released; see the RedPill page for more info.