Elementary OS "Luna" Released
If OS X and Ubuntu had a baby, this is probably what it would look like. :)
Website / Download (32-bit, 64-bit) / Blog
Luna has been engineered from the ground up to be light on its toes. It starts up quickly, logs in instantly, and uses the bare minimum of resources so that your apps enjoy a speed boost as well. And with Luna, you get the same Linux foundation chosen for the world’s fastest supercomputers.