I once attended a seminar by Lloyd Kaufman of Troma fame. It was about how to make your own movie. One of the tips he gave was to make friends with dentists because a) they have money, and b) they're bored at work and want to do cool things. I kid you not.
(AND: now that I think about it, in the room next door, Matthew Lesko was giving a seminar. Once again, I kid you not.)
I'm at the age now where I'm seeing some of my old friends I keep on Facebook actually start up their own practices. Guy I bought weed from in high school? He's a dentist now. Guy who pissed in my laundry hamper? Heart surgeon.. etc.