I have been playing with Quartz Composer on OS X a little bit. I know these folks were talking about a screen saver on the 2600, but here's a first go at an Atari logo screensaver for OS X as a Quartz Composition. After I get the visuals hammered out, I need to figure out XCode so this can be a pretty .saver file, but for now (if you like), you can drop the .qtz file into your Library/Screen Savers folder and voila...