Most of the reports that you hear often start with, "People who were alive in 1963 can always remember exactly where they were when they heard the news." For an entire generation of Americans, the day's events are seared in their collective memories.
My mother told me her story many times. She was bowling in a women's league, while my brother was home sick. He called the bowling alley to tell my mother what had happened. She immediately asked for the news to be announced over the bowling alley's PA system. Everyone in the alley stopped bowling and went home to learn more. The rest of the weekend was spent watching the news on television. Of course, in 1963, there were no cable news channels, and only a few TV channels at that. She always told me of watching Walter Cronkite deliver the news in his shirtsleeves - then as the afternoon turned to evening, he suddenly realized he was not wearing a suit jacket. Later, when Cronkite returned to the air, he had put on his suit jacket.
There are any number of stories about this seminal event in American History. Of course, there are the conspiracy theories as well, and there have been a number of "alternate histories" of what could have happened had JFK lived. Where I work, there are countless records about the JFK assassination and I have worked with researchers here and in a previous archives job who were looking into the story of the day's events.
As a "history geek," I can tell you with ease where I was when other significant events took place in history though I was not alive when JFK was killed. The death of JFK was most certainly a defining moment in history and it brought a generation together not seen again, in my opinion, until the September 11 attacks nearly forty years later.