http://www.astronomynow.com/news/n1211/15rogue/
A possible free-floating exoplanet, drifting through interstellar space without a star of its own to orbit, has been discovered a hundred light years from Earth. If confirmed, it will be the first of its kind to be proven to exist - and there may be billions more like it out there.
This is so cool!

Still, I can't help but put this in. Just to throw it out there.

http://www.youtube.com/watch?v=-bzWSJG93P8

What if it's not a planet... per se?