Day of the Hunters by Isaac Asimov - The little old man had a new slant on the mystery of what happened to the great dinosaurs...
It began the same night it ended. It wasn't much. It just bothered me; it still bothers me.
You see, Joe Bloch, Ray Manning and I were squatting around our favorite table in the corner bar with an evening on our hands and a mess of chatter to throw it away with. That's just the beginning.
Joe Bloch started it by talking about the atomic bomb, and what he thought ought to be done with it, and how who would have though it five years ago. And I said lots of guys thought about it five years ago and wrote stories about it and it was going to be tough on them trying to keep ahead of the newspapers now. Which led to a general palaver on how lots of screwy things might come true and a lot of for-instances were thrown about.