[UCSC via Slashdot] March 16, 2880, is the day the asteroid known as 1950 DA, a huge rock two-thirds of a mile in diameter, is due to swing so close to Earth it could slam into the Atlantic Ocean at 38,000 miles per hour. The probability of a direct hit is pretty small, but over the long timescales of Earth’s history, asteroids this size and larger have periodically hammered the planet, sometimes with calamitous effects. The so-called K/T impact, for example, ended the age of the dinosaurs 65 million years ago.

Pretty interesting stuff. The simulation can be found here.