I was a sophomore in high school. I remember I had just got out of my German II class (2nd period) and was headed towards gym classes when one of my friends ran up to me in the hall and started going on about something involving airplanes hitting a building. He was really out-of-breath and took off shortly thereafter so I really had no idea what was going on. I actually went all the way through gym (3rd period) and it wasn't until 4th period in my AP European History class that I finally found out what was going on. The teacher had a TV in the classroom and we spent the rest of the day talking about what had happened.
It really sucks there are already so many of these "Do you remember where you were when...?" moments in my life.