After waking my PowerBook from sleep, the the stripped background for the menubar and the translucent background for the Dock were patterns of weird colors like green and pink. But, the computer was still responsive, and after using the Dock and menubar a bit, these colors "refreshed" and the regular backgrounds were back. This has never happened to me before. Has this happened to you? Could this be component (video card) failure, or system file corruption? Or could this have been a freak incident?