A space rock about a quarter-mile-across whizzes by Earth tonight (Nov. 8, 2011). The asteroid, called 2005 YU55, is coming closer than the Moon’s orbit.
But don’t bother taking cover—the asteroid will miss Earth by 200,000 miles when it reaches its closest point around 6:30 p.m. Eastern time. Its gravitational influence will have no detectable effect on our planet.
Although 2005 YU55 has been classified as a potentially hazardous object, NASA’s Near Earth Object Program says this asteroid poses no threat of colliding with Earth over at least the next hundred years.
The asteroid is way too dim to see with just your eyes. But if you have at least a 6-inch telescope, you could try to spot it. Sky & Telescope’s website has a good article about the asteroid with a link to a finder chart.
For something easy to spot with your eyes alone, try Jupiter. It's that bright "star" blazing away in the east after sunset.