Sure, asteroids and their ilk impact the earth all the time. Of course, most of them burn up in the atmosphere, so I don't guess they actually impact the SURFACE, but they do impact the atmosphere.

A bit more serious, wasn't the 2012 asteroid one of the ones they thought at first might hit and then they redid the calculations and found it was going to miss us by a pretty wide margin. I think this was one of the first ones that was hyped up, probably because it was around the time of Deep Impact/Armageddon.