Questions like this remind me just how old I am though it helps that Brunswick737 is so young. And yes, the movie 'War Games' provides an excellent explanation of the Defcon scale even if it's basically light, 'popcorn' cinema. L-188, just FYI, the defense computer in the movie was called the W.O.P.R. (for War Operations Programmed Response) although it was also referred to as Joshua, after the dead son of its' designer. Nice moral lesson about war in the film ("The only winning move is not to play.") but it was preposterous on an epic scale.
"The only time we went to DEFCON-2 was during the Cuban Missile Crisis."
Another thing that reminds me I'm old. Unlike most of you, I actually remember this (I was 7 at the time) and it was indeed, a scary time. Very tough for my 2nd grade teacher to explain it to us kids (try softpedalling the Armegeddon scenario!) but she did a good job. Then Soviet leader Nikita Khrushchev's ominous "We will bury you!" threat still echoes in my head and we went through all those solemn civil defense drills which probably wouldn't have done squat in an actual nuclear war. Thankfully, he turned out to be a paper tiger in the face of JFK
's ultimatum and pulled the missiles out of Cuba. I do believe, however, that we were frighteningly close to an actual nuclear conflict; hopefully, this was as close as the world will ever come to one.