We did get a useful learning moment out of Earth Hour. My son noticed coverage of it on 3 News, and when they got to the footage of people lighting up candles insteading of switching on the lights, he asked "But wouldn't burning candles be worse for the environment than leaving the lights on?" Correct, mate - all the so much worse for the fact that the bulk of our electricity's being generated from renewable resources. But leaving the lights on doesn't give you that warm feeling of superiority generated by participation in meaningless gestures.
My daughter's contribution to Earth Hour learning moments was to ask whether the windmills above the town are supplying our house's electricity. In the interests of promoting national goodwill and co-operation I told her "Only partly, my girl - it all goes into the national grid, and our house gets its electricity from the national grid. I'm afraid those dirty, dirty Auckland huas are also getting our good clean Manawatu electricity." (I read this on a protest pamphlet a couple of years back, so it must be true.)