Many home electronic devices, from televisions to microwave ovens to electric toothbrushes, continue to draw a small amount of power even when turned off. Sometimes, this is to allow the device to respond to a remote control; other times, it's for little more than a light or (yet another) digital clock. This "idle power" draw (sometimes called "phantom use") may be a trickle, but can really add up with lots of gizmos. Putting these devices on power strips doesn't always help, as you can easily end up with a situation where you're sending power to every item on the strip when you're only using one.
Treehugger profiles a couple of different options to resolve this problem: the Wattstopper and the Smart Strip, two power strips able to sense when a plugged-in device goes idle and shut the power down completely. The prices vary, but they seem to be worthwhile additions to a household with more gadgets than time.
The one thing they're missing, though: a way to communicate the information about device activity back to a central monitoring system, so that you can know as much about how your stuff works as your stuff does.