Just talked to my history class about how this is a day that everyone remembers what they were doing, much like JFK. The kids I have now were 2 years old when it happened which means they have no clue of the magnitude of the situation. I showed them a great video called "The 9/11 Tapes: Chaos in the Sky" and reminded them that this is the reason we are fighting the war on terrorism and we shouldn't forget the tragic events of 9/11. Sometimes our memories get short and we lose sight of why we are hunting these bastards down.
If you haven't seen this video, check it out. It is all of the events from the air traffic controllers and Air Force perspective. It's really interesting.