A few months ago, a blog post popped up suggesting that because it takes fewer watts to light a black screen than a white one, A black google could save energy.
I'm a big fan of slacktivism, so when an opportunity presents itself to put forth virtually zero effort and still feel good about myself, I generally jump on it.
Blackle is such an opportunity. It's an primarily black version of Google's search engine (just search, no spiffy maps or images, etc). According to the website, they've already currently saved 4,700+ Watt hours.
They suggest setting your homepage to Blackle instead of Google to continue saving even more energy.
I certainly think the is the best idea ever. How else can you save the planet while searching for free porn on the internet?