As a method to save on home electricity bills, as well as reducing your carbon footprint (thus helping to save the planet) I have discovered "home energy meters".
Home energy meters measure the electricity consumption at the main electricity meter and transmit the result to a wireless unit, which can be in your kitchen, living- or bedroom.
Thus, if your kids forgot to turn of the TV and Wii in your basement, you know about it and can tell them to turn it off, without first trudging into the basement yourself.
You also know at any time how high your electric bill will be and get warnings when the energy usage is especially high.
I have ordered the Efergy energy meter and I expect it to arrive in the next week here in Germany. I got my unit from here: home-energy-meters