Sydney, Australia has just started doing it today (as I'm writing to you in the Pacific Standard Time zone), and more cities are to follow.
For 60 minutes tonight, March 28 at 8PM local time, everyone is supposed to shut off their lights and "power down" for an hour.
I don't think that means unplugging your refrigerator or anything like that, more than it means turning off all the lights in the house and not using appliances.
Here's the website for details: Earth Hour US - Earth Hour 2008. The event is being sponsored by the World Wildlife Fund, here's a link to their site too: WWF - Endangered Species, Wildlife Conservation, Animal Habitats. They have some really slick animal adoption programs available that allow you to take ownership of saving species...definitely worth your time to check out...I adopted a Siberian Amur Leopard for my folks as a $50 gift for the holidays.
Sorry, digressed there. So if you want to put some simple and easy environmental stewardship into action, the Earth Hour is an excellent way to do it!
I hope this starts to become a recurring event. S