Comet
Doomsday comet breaks up before making a pass at Earth
According to Space.com the supposed doomsday comet Elenin is breaking up and won’t come crashing down on the Earth.

Amateur astronomer Michael Mattiazzo of Castlemaine, Australia caught these two images of comet Elenin on Aug. 19 (left) and Sept. 6, 2011. The images show a rapid dimming in the comet, possibly hinting at its disintegration. CREDIT: Michael Mattiazzo
So all you Doomsday Theorists out there, oh well. Find something else.
Here a link to the Space.com story.