Last night it was possible (not in Seattle - clouds!) to see an asteroid pass the Earth at just 0.000482 AU (or 46,478.5 miles). That is well inside the moon's orbit which is approximately 250,000 miles, and about twice the distance of a Geostationary satellite (23,000 miles). So there was no chance it would knock out a DirecTV satellite and cancel the last few episodes of "ER".
But, if this did hit the Earth it is about he size of the thing that hit Tunguska back in 1908 - so it had the potential to cause a mess. Estimated size is 30-40 meters. It was about 11th magnitude so it was a pretty dim target to find, but with a telescope pointed in the right area taking a series of photos it would be possible to see it moving against the stars in the background.
This video was taken by Robert McNaught - yeah the same guy that got the bright comet named after him.
APOD also had this familiar photo from 1972 published in the site today. This is one that skipped off the atmosphere and went back out into space. But performed a nice little airshow on it's brief visit.