The only time the AI launched a Nuke at me was in Civ I. I was happily building the spaceship and I recall that one of the AI's had built the Manhatten project. I hit the end turn button....only to see a few seconds later a missle marching its way across my screen to one of MY cities

. Berlin evaporated to half its population and all the units dead or damaged.
I think i shut the power off and went to bed right after that.
ah those were the days..........