In my office we have four computers on a LAN: Two Ubuntu machines and two Vistas. Each is on its own power strip with surge protection, no UPS. The ADSL router is on a separate outlet. When we come in in the morning, before turning on the lights, it can be seen that the router has power, as do all four of the power strips. The computers can all be powered on without turning on the lights, and they have internet connection so I know that the router is powered on even before turning on the lights.
If one turns on the lights before booting any of the computers, then one of the Vista machines boots up when the lights come on. It will stay up even if the lights are then turned off. Thinking that maybe something is sending wake-on-lan I unplugged the network cable and tried again, sure enough the possessed Vista machine boot right up when the lights come on.
What might cause this? Should I document everything in a video to post to youtube to prove that the power strips are in fact powered even when the lights are off?