Gliese 581 C is a temperate planet like Earth, according to recent findings from the Eso 3.6m Telescope in Chile. With temperatures ranging from 0 to 40 C, if it has water, the water would be liquid, making it habitable for us, and probably other life forms as well. Future missions will analyze the planet for signs of biological activity such as chlorophyll and methane. Gliese 581 C is 20 light years away, so it'll be a while before we can actually go there - unless we have a breakthrough, in which case, party at Marklar's place.