This is why we buy good glass for our cars.
I had a similar thing happen, rock flew out from the side of a freeway and hit the crome around the windshield in my mom's jeep. Didn't hurt the glass but it sure left a huge bang in the metal. I was in the seat it would have entered too...not good times.
1969 bug (pre wreck) going down the local highway (99w) and a van kicked up a rock, chipped my windshield, and my brand new pretty car had a huge crack in the glass in no time.
Sacraficial I guess...sad stuff...but its better than eyes full of glass, cut up body parts, and worse yet, loosing control of your car...

*...considers having the leak in his windshiled fixed but remembers it has no cracks or chips yet....murphy...*