I saw it somewhere some time ago (1-2 years or so) a "virus" for Leopard that you could use to prank coworkers etc. Once installed it would make different components on the desktop, like menu bar, icons, windows, break apart and fall down to the bottom of the screen. The physics was pretty impressive and fun to watch. Afterwards you could just uninstall it. 
Anyone know what I'm talking about?
Anyone know what I'm talking about?