Waht are the best non-profit ideas that are viable in North America and in Africa?

Microfinancing/community micro-loans. It is not pure non-profit but almost... (you can build net interest margin to primarily provision for expected charge-offs). 

That was a great answer!  You might also want to consider a program that identifies intelligent youth in un- or underdeveloped areas and provides mentors and avenues for them to go to universities so they may contribute back to their community on a greater scale.