I've heard rumors that Abuja, Nigeria is planning to bid within 20 years.
I think that for sure the first African games will be in Cape Town, but I think it will be in 2024 or 2028, because 2012 will most likely be in Europe (Paris) , then hopefully 2016 will be in South America (Rio) , then I think the IOC will have a hard time going to two completely new regions back to back and ignoring cites like New York, London,and Madrid, so I thinmk it will go like this:
2012-Paris
2016-Rio
2020-New York
2024-Madrid
2028-Cape Town
Just a bit of thinking on my part, thanks.