Because everyone has one here's mine, and it's actually slightly unique:
On 9/11/2001 I was at home (SF Bay Area) working at home on our company website because at the time I had better software tools at home (I forget why - something to do with a Mac no doubt.)
The phone rings and it's Catherine at work.
C: "Are you watching TV?"
Me (totally taken aback by the weird question): "Of course not, what do you think I do here?"
C: "No really, go turn on the TV. Someone has crashed planes into the trade center towers and one has fallen down. This is bad."
The rest of the day was spent exactly like everyone else's. Glued to the TV in shock.
That evening I get a phone call from my friend Pierre whose wife Betsy is pregnant with twins.
P: "We have news."
I pretty much cry out "No! No! Please no more news. I can't take any more."
P: "No, we have NEWS"
Finally getting that he means the twins were born, I reply "Wow congratulations, how did you get anyone to pay attention to you at all?"
He joked about the doctors keeping half an eye on the TV screen.
The poignancy of getting that news at the end of that day really brought home to me that there is a future. And I will always know James and Katie's birthdays. Happy birthday. And happy birthday to my (unrelated) friends Celia and Cheri who also share this birthday with them.