Place a beautiful water effects as your desktop's screensaver.
LotsaWater for Mac is a free water-themed screensaver that looks quite good on newer Macs, even those with retina displays. The screensaver is exactly as it sounds, a rippling water effect that takes over your desktop when the timer goes off for your screensaver. It looks fantastic and it offers a nice alternative to the screensavers built into the OS X system.
Xmas screensaver that the whole family will enjoy.
Like Berkeley's old After Dark.
OpenGL screensaver module.