I have been working with Johns Hopkins Center for Talented Youth for over 4 years now, and have loved it. I really like working with those students. The only drawback is that I am limited to 27 hours a week and I'm limited by enrollment. This is a slow time of year and I'm doing about 10 hours a week.
Recently I was approached by Udacity to be an independent contractor. I have been working with them since March and I really enjoy it.
In May, Udacity changed their business model --> now you can sign up and get started as soon as you want. Before they worked in cohorts, and you might have to wait a month to get started. They've also changed the mentorship model. They assign students to mentors, which I am one. You get one 1:1 session a week, can you can ask be questions through there student hub. I login a few days each day to check in on my students.
If you are interested, and use this link, we both get $50 off a course, and I have a few I want to try.