Every Ghanaian has a name based on the day of the week they were born. There is one male name for each day and one female name for each day. I think this is done all over Ghana, although the names may vary in the north. In my part of Ghana, names like Kofi, Kwesi, Kwame, and Yaw are all male names. So men generally have one of these and a Christian name and they can go by either one (sometimes they use both). Kofi Annan (the UN Secretary General is Ghanaian) means that he was born on a Friday and he is the fourth born in his family (Annan means four).
I was born on a Tuesday (or at least I was for the purpose of my Ghanaian name). I never used a Ghanaian name when I lived with my homestay family, but I quickly got tired of being called obruni or one of its many derivatives. And when I introduced myself as 'Ari,' I was usually either called Harry (little do they know that no American baby has been named Harry since 1953) or Eric (not terrible, but it's not me). I needed to give people a name they understood and could easily remember.