We've just finished participating in Earth Hour 2012, where people are encouraged to turn off all unnecessary electricity for an hour at 8:30 PM (local time) on the last Saturday of March. This year we did even better, because we turned off all the lights and information technology (computers, etc.--but we didn't unplug things like our internet router or our refridgerator) and spent the hour reading by oil lamps.
So we got to experience the past (in a minor way). We discovered it was dim, smokey, and sooty.
So after the hour was up, we turned on one lamp to continue reading (and I'm posting using my computer's battery), but left all our other electricity off. We like doing this, both as a symbol of willingness to contribute to our planet's energy and environmental problems, and as an experience of our past (and hopefully, not our future....)
We found out about Earth Hour a few years ago from an educator from the NC Zoo, Miss Melinda. Earth Hour began in Australia, and she was Australian, although I don't know that is why she knew about and/or publicized it. Anyway, she sent out the information to our Zoo Club, and we've been observing it ever since. Unfortunately for us, Miss Melinda has gone back to Australia, but we will never forget all the lessons she taught us---including the importance of participating in Earth Hour.