I am running through my memory bank, and can't really think of one outside friends and family.

OTOH, I seem to be "that stranger" whenever possible. And that's mighty satisfying. People I've studied under or assisted with computer support have a habit of getting Nobel Physics Prizes. I have aggressively looked for and found, owners of lost cell phones and ipods.

Sorry to disappoint!

BTW, a friend is an M.D. While I was visiting his home, his cat scratched me, and I asked if he had any betadine. He didn't. So, you never know. Having been in the Coast Guard "Semper Paratus" always ready, I tend to bring small tools and first aid with me when I drive, but the only application so far was someone whose battery died in the SFO cell phone lot around midnight, and I had the jumper cable handy. The more serious one was when I was coming home and saw a light flickering in the neighbor's detached garage. Well, he wasn't welding. It was an electrical fire, and I made sure they knew about it post haste (they were watching TV in the front room). And that's about it.