I was just reading an article about the Chance of an Asteroid Hit on Mars:

LOS ANGELES (Dec. 28) - The chance of a football field-sized asteroid plowing into Mars next month has been increased to 4 percent, scientists said Friday after analyzing archival data.

Though still a long shot, some researchers are hoping for a cosmic smash.

Right now the chance is only 4% but its an interesting event none the less if it happens!