NASA/JPL's Near Earth Objects Program
Neat site detailing known celestial objects (asteroids, comets, meteors) which cross or approach our orbit, research into such objects, strike probabilities orbital diagrams (java app animating orbits), all known orbital data...Also good info on known impacts etc...
Very fun site...
...Look into 1950 D...Especially if you plan to be living on the east coast in 2880 (can you say 200ft Tsunami)......