Well I don't want to talk to him about his inventions, I don't think - while I think those were really interesting.
And I don't want to ask him any question I can just google, so 'factual statements' are boring.
I think I might ask him something about how feels society will transition into the rapidly expanding scientific functionality we are achieving in the next decade, but something -more- specific than that. He'll probably talk about that at one point.
I guess I should have MULTIPLE questions prepared, in case someone asks him something I wanted to ask him before me, or in case he mentions it during his presentation. Mind if I still your question (or the spirit of it) as one of the possible questions I can ask?
Ask him about his suppliment intake. The guy is up to around 200 pills a day! Ask him if he's ever gone off the suppliments, does he notice the difference, what suppliments he could never live without. You might get some good insight with that topic.