Asteroid 2012 DA14 is coming very close to the earth and if it's going to hit, will be slated to hit February 15-16, 2013. Here's a picture showing its closest approach about 7:00GMT.
Now to put this into perspective before we call this the apocalypse, the estimated size of this thing is 61 meters or 200 feet in diameter. Worse case scenario is this "whole thing" makes it through unbroken. I noticed in astronomical studies that something makes a crater about 50 to 100 times its size from the tremendous kenetic energy. Let's take worse case 100x its size is "total distruction". That would be a 10,000 foot radius or about 4 mile diameter crater. Yes, that's large encompassing about 12.5 square miles. But how many square miles is the earth? Remember those formulas in geometry class where a sphere is 4xPIxRadius^2. That makes the earth almost 200,000,000 square miles --- 12.5 is a drop in the bucket compared to that.
Going one step further, suppose the "immediate effects" are another 100 times the distance of the crater. And by effects I could mean anything from devestating wind and fire storms near the crater to a shaking house and only broken window glass say 200 miles away, most damage being minor. The area involved would be about 100 x 100 x 12.5 = 125,000 square miles.
Let's put this into perspective. The odds of any area on the earth directly affected is 125,000/200,000,000 or about 0.06%, even with effects that wide. Or to put it another way, about 99.94% it won't happen to you (area-wise, not population-wise).
This does not take into account if we were unlucky enough for it to hit a large city, or near to a shoreline that there may be enough desctruction to say, have economic impacts from infrastructure damage -- those are indirect results hard to calculate.
From the picture, I would say that it looks like if it were to hit dead center, that it would Happen somewhere between the longitudes of Europe and NY city. Probably in the Atlantic ocean somewhere. That may cause costal emergencies and evacuations (Tsunami). however, the orbit may be deflected more toward the sun (western US longitudes) or skim the earth away from the sun (middle east longitudes, e.g Indian Ocean). We just don't know.
