I am a master's student and am looking for ways that link a certain social commitment with **serious** math. Since I have not found such an overview yet and in order to raise public awareness of such opportunities, I decided to pose this question (feel free to put this question on hold, if you feel that it violates any of your rules).

Recently, a friend told me that he will work as a TA at the African Institute for Mathematical Sciences. I just saw that more senior mathematicians can go to these institutes as lecturers.

In this sense, I am looking for similar opportunities where people can use part of their free-time to do serious mathematics in developing countries on a rather voluntary basis. Are there similar slots available somewhere?