Do you have a mentor/mentee?

I'm seeing a lot of developers advocating having a mentor, who will guide you and help you become a better developer.

I'm also seeing a lot of developers advocating that you should have a mentee, whom you will teach and help.

I've never had either of that officially, but I help people when they ask me a question personally anywhere on the web. I used to be active on Stack Overflow and answered a lot of questions there. I also learn from people by asking questions, writing emails and reading open source code.

Do you have a mentor/mentee and how did you meet them?