There used to be a great rotating cube animation in OS X when you locked the screen or switched users with fast user switching. It was especially impressive on the 24" iMac screen (I remember being delayed going to lunch one day because everyone in the office wanted to see it in action).
Older ThinkPads had accelerometers in them to detect when the machine had been dropped and park the disk heads in the instant before it hit the floor hard to avoid data destruction. A Linux driver was written for this accelerometer, and someone had configured Compiz to shift to the virtual desktop immediately to the left or right, depending on which side the laptop had been smacked.
A couple months ago I loaded compiz on my Debian box. I messed with a lot of the eye candy, then settled into a few fun gee-gaws, like switching virtual desktops via rotating cube, windows that desaturate when not focused, etc and still am using it today. Puts a little whimsy back into my work day.
There was one screensaver that would make your cube slowly rotate while all your windows (still displaying live content, mind you) would swirl around on the inside like papers caught in a small tornado.
Rotating cube desktops are such good UI/UX I wish they were more mainstream... it really helps compartmentalizing tasks into different virtual/mental spaces
