Slate and Tree Hugger have teamed up to create an eight-week challenge to track and reduce your carbon emissions. Each segment has an article about ways to reduce your emissions, and then a quiz asking you to pledge to different methods of reduction. At the end of the whole thing, the first 500 people to reduce their emissions by 20% even get a free T-Shirt. And don't we all love free T-Shirts?

So head on over and learn a thing or two, and help the world out.