Perplexed said something smart, but here are my drunk brainstorming ideas:
Do you believe in God? Why or why not? (people are usually willing to answer this, but they'll get offended in a hurry if you argue)
What experience in life have you learned the most from?
What was your favorite subject in school? Do you still follow it?
Do you think it's worthwhile to give to charity? Which ones? Do you give to them? (see God question caveat, and the last question is extra offensive if they have to say no)
What do you think about him? (Mention someone you both know personally or indicate a person who can't easily overhear)
What do you do when you don't have to do anything else?
I like some of those, particularly the last one--I've seen something similar, which was "what could you talk about for hours?"
I'm reluctant to ask "most," "least," or "favorite" questions, because almost nobody has good prepared answers, except to the trivial ones like "favorite color." Which is not an effective question for getting insight into someone's worldview.
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