Another simple gesture: Earth Hour

Like BYOBlue for Earth Day, Earth Hour — which is this Saturday, March 29, beginning at 8 p.m. — has a two-pronged thrust: it's an easy doorway into larger changes we can make in our daily choices, and it sends a larger message. It starts by simply turning out the lights for an hour. From the Earth Hour website:

On March 31 2007, for one hour, Sydney [Australia] made a powerful statement about the greatest contributor to global warming — coal-fired electricity — by turning off its lights. Over 2.2 million Sydney residents and over 2,100 businesses switched off, leading to a 10.2% energy reduction across the city. What began as one city taking a stand against global warming caught the attention of the world. In 2008, 24 global cities [it has since risen to over 30] will participate in Earth Hour at 8pm on March 29. Earth Hour is the highlight of a major campaign to encourage businesses, communities and individuals to take the simple steps needed to cut their emissions on an ongoing basis. It is about simple changes that will collectively make a difference — from businesses turning off their lights when their offices are empty, to households turning off appliances rather than leaving them on standby.

The website allows you to sign up to "receive useful tools and tips to help you get even more involved"... and that's where the real juice is.