Everyone has stories, most better than me. I find my most vivid memory of experiencing him as an adult was that every time you spoke with him he'd have had some completely flabbergasting new life experience you'd never imagined. He was a guest on something like the second trip to China after Nixon, took seminars with Oppenheimer at Berkeley (he tended to call him Oppy), and may have been invited to help create an early ATM. The list goes on and on.
One Christmas, we were talking about how difficult it is to assess the accuracy of an algorithm when you only get a few tries because running it is expensive; he promptly told us about his experience with this problem, which he encountered driving plutonium nuggets across Richland, Washington. After the video from the ACM conference on personal workstations got published here, I learned for the first time he'd been fired from MIT three times for insubordination, and I never got a chance to ask him what the story there was...
Oh! And he actually made a physical turing machine good enough to do fairly sophisticated computations on. It ended up in my father's intro CS class at Princeton for many years.
And HN will of course appreciate one of his favorite one-liners:
Did you know that 49 is the lowest number that can be expressed as the square of 7 in only one way?