http://www.earthhour.org/

Created to take a stand against the greatest threat our planet has ever faced, Earth Hour uses the simple action of turning off the lights for one hour to deliver a powerful message about the need for action on global warming.

This simple act has captured the hearts and minds of people all over the world. As a result, at 8pm March 29, 2008 millions of people in some of the world’s major capital cities, including Copenhagen, Toronto, Chicago, Melbourne, Brisbane and Tel Aviv will unite and switch off for Earth Hour.