John Robb has written extensively and well about the role MEND guerrillas have played in Nigeria.
So much for West Africa. Some of you may be wondering whether East Africa has any groups analogous to MEND.
The answer is either a definite "Yes," or a "there very well could be." Kenya has an urban-slum based group with a messianic ideology comprised of alienated youth known as Mungiki, who could tomorrow become in Kenya what MEND is in Nigeria today.
Kenya is incredibly corrupt. I don't blog about Kenya much because apparently nothing happens there. It just festers. The New York Review of Books has an article about Kenya's corruption. But Kenya abouts Somalia; so the question is not whether it will boil over, but when.
Here is a backgrounder on Kenya's Mungiki.