I doubt anything can compete with this story, but challenges welcome:
After Greco's talk, in the middle of a question by Christina, John passed out! He was out for roughly 30 seconds, during which I was a totally useless observer; good thing it was not a serious emergency, 'cuz I'm worthless on that score. Anyway, he finally revives, to the relief of all, sits up, and says, "Man, that was a tough question!"