I was in 1st year at uni and living in the Halls. One of the guys said something about America being "under attack" at breakfast so after we finished our toast we all piled down to the TV room. I didn't leave my seat till about 4pm that afternoon, I don't think any of us went to class that day.
Mostly I remember that we had 3 guys in our Hall from New York - two of whom had Dads in the fire service. It was sickening to think that something had happened to people they knew and they couldn't find out anything for ages because of the lines being jammed in the US. The manager drove him down to the US Embassy in the afternoon and I remember us all being really nervous about what was going to happen.
Turns out one of the guys' Dads was late for work as he missed his train - his shift were the one's that went up the tower and didn't make it back down

But this guy's Dad was OK. Still get goosebumps thinking about it. Can't remember what happened to the other guy's Dad but he was all right too.