At the time I worked for a defense contractor in northern Virginia. We heard about the first plane, turned on the TV's in the conference rooms, and saw the second one it.
I had friends working in the Pentagon, fortunately none were hurt that day.
IIRC schools let out and so did most of the government buildings. I went home as well but eventually just had to get away from the tv so I went to the barn to cry on my horse's shoulder.