My roommate's mom called and said we needed to turn on the TV. My roommate was at class, but I turned on the news. My experience was virtually identical to yours - I saw the second plane hit and immediately realized this was intentional. Adding to the surreal feeling that we all experienced was that I had just done a pretty in-depth study of how the towers were constructed for one of my classes the previous semester. I'll never forget how crystal clear the sky was that day, or the sick feeling I had in my stomach. I'm sure many people have very similar memories.