I was ten at the time. I was at a friend's, meeting him for the first time since he moved away two years earlier (actually haven't seen him since, I think). My dad picked me up some time in the afternoon (well after everything had collapsed, but apparently he didn't have the car radio on, because I can't remember him saying anything about it). Anyway, I was driven straight to a scout meeting, where one of the guys said World Trade Centre had been terror bombed. I didn't believe him at first, but when my dad picked me up afterwards, he told me. I watched the news replay the events half the evening, before I was told to go to bed.
Other such events I can remember where I were at the time of its happening was the Columbia disaster (was visiting a different friend for the first time), the Boxing Day Tsunami (sleepover at a cousin's, woke up to the news) and the terror attack in Oslo (was at home, heard the explosion twenty kilometres away. Dismissed it at a thunderclap at first, then my father, who was in the next room, told me to watch the news. I sort of followed the Utøya massacre at Facebook (friends warning each other against calling friends who were on Utøya, because they were hiding and a phone calling would blow their cover). Now THAT was a weird sensation).
EDIT: I might also add the fire aboard the cruise ship M/S "Nordlys" in Ålesund. The fire, which started this morning, may be a major event, because it looks like the ship is going to capsize tonight.
http://www.vg.no/nyheter/innenriks/arti ... d=10010275
Two dead and nineteen injured, none missing. The ship is devastated by fire, but is towed to shore and they fight to stabilize it.