I follow a lot of the stuff the NASA's JPL publishes and creates about neat, cool, space related science stuff... and this one is a bricks to be shat one here:

It's the asteroid 2012 DA14, 50M in diameter and weighing in at an estimated 180,000 tons (basically a very bad day for anyone near where it hits)... it's going to pass Earth by a mere 17,200 miles. For reference, the moon is 238,900mi away, one 14th the distance, and closer than GeoSync satellites . NASA has stated that the asteroid has no risk of hitting Earth, and on a return trip (laws of gravity) a .002% chance of hitting in 2080 and 2109 (our future relatives are safe from this rock).
More info here.