Earth Hour is being held on March 23, 2013, from 8:30 to 9:30 pm! You can join the millions of other people participating across the globe by turning off all non-essential lights, appliances and other electrical devices in your household during this time period in your timezone.
Earth hour has an impact beyond the measurable decrease in electricity consumption (up to 10% lower, as measured in Sydney, Australia in 2007 (x)). It raises awareness of environmental issues such as climate change and energy consumption, and it encourages individuals, businesses and governments to take responsibility for their ecological footprint, opening dialog regarding environmental challenges.
Read more at the Earth Hour website.