Everybody's going ahead and giving Jimmie Johnson his fourth Sprint Cup championship, but hold on! We've still got races to run! What's that you say? You say there's no way anybody's catching Jimmie? Balderdash, we say! Mathematically, it's still possible -- phenomenally unlikely, but still possible -- that someone could catch Jimmie. Using this breakdown of NASCAR's points system, let's take a look at the ways things could go south for the 48 car. His closest...