Ok, I have to officially turn in my nerd card for this one.

Anyway, SysInternals has a screensaver that simulates the Windows BSOD (Blue Screen of Death). It was awesome, and became a running joke for a couple of days. Incredible to say the least. It really had me goin.

http://www.topshareware.com/Bluescreen-Screensaver-download-552.htm