No, but there may be on
Gliese 581g (or Zarmina as affectionately dubbed by the planets discoverer). By now, most people are aware of a recent discovory that confirms the existence of the first "earth like" exo-planet occupying what astronomers refer to as the "habitable zone" of an extra solar star (in this case the red dwarf star
Gliese 581). In a recent interview the astrophysicist who made the discovery, Steve Vogt, opined on his belief that life most likely already exists in the termination zone of Zarmina. This region represents the planets own "habitable zone" in that, being tidally locked to its parent star, it's the most temperate strip on the planet where biological life as we know it could potentially thrive:
"I'm not an expert in biology but when you read about the conditions under which life took hold on this planet – it was a terrible place 4 billion years ago, with no oxygen. Yet life came on the scene quickly. Something hit Earth so hard it broke off a chunk that created the Moon. And yet life kept coming back over and over again. You learn from that that it's hard to stop life."
Habitable zone eh? Makes me wonder about the habitable zones we each occupy in our lives. Do we find a place so comfortable that it becomes easier for us to simply exist rather than really "live"?