John Winston Lennon, MBE (9 October 1940 – 8 December 1980)
This was one of those events where they say you will always remember where you were, at what you were doing, when you heard the news. I was 14 years old, and I was tucked in bed (it was a school night) listening to my transistor radio. My parents were probably watching TV, because in the US it was "Monday Night Football" night. I think I remember them telling me the news and I changed the radio station so I could find an update.
This clip I found on YouTube seems to indicate that the majority of Americans learned of John Lennon's death while watching the football game. The announcer, the late Howard Cosell (along with co-announcer Frank Gifford) announced John's death during the game.
RIP, John Lennon.