I never charged money for it, but since I live in Japan and used to teach English for a living, I used to teach English to retired people in the area. I stopped because I don't actually have enough time any more, but it was very rewarding. I'm thinking of starting up again, holding sessions in the pub and charging beer as payment.

Now that I think about it, it's how I got together with my wife. I met her running in a marathon of all things and she wanted to learn English. I said I'd be happy to teach her and after 2 lessons I asked her out on a date :-) I never did teach her English beyond that!