The Best Way to Deflect an Asteroid (New York Times Magazine)
A two-year study by a Scottish researcher rated the "mirror bees" method as the best way to protect Earth from an asteroid impact, should one of sufficient size be headed in our direction. This method involves sending mirror-equipped satellites into space to surround the asteroid, reflecting sunlight onto a single spot on the asteroid in order to burn a hole in it and release a stream of gases that will move it off-course.
The Engineer has a much more in-depth article about the study, and Wikipedia's article about asteroid deflection strategies provides some additional background.
The New York Times Magazine article about asteroids is actually part of their quirky cover story this week, "The 7th Annual Year in Ideas." Some of my favorites: