I spent some time during 2014 and 2015 on the Nikumbuke project in Kenya. Nikumbuke provides - among other things - education to women of 7 small villages in Kenya. The age varies but what they members have in common is that they didn't finish elementary school for a number of reasons.
I fell in love with the project and the amazing members of the project and plan to go back in 2018.
Read more about the project and learn how you can contribute as well at: https://fromone2another.org/project-nikumbuke/
In early 2015 I visited Ifaty, a small village in south-west Madagascar that sits just by one of the biggest barrier reefs in the world. The reef is endangered and Reef Doctor teaches the people living by and from it how to both use the reef in an optimum way today and how to preserve it for future generations.
I have never had a more steep learning curve than at this project. If you want to learn about marine ecology this is the perfect 101 :)
It's been a while since I had time to hang out on Quora, but you can find some of my old answers there. As for github, my public contributions are unfortunately limited and private ones have beeen low for the last year, but I like to keep the link here as a statement that I'd like to do more.