Well I don't know alot of fruits that aren't already known everywhere else on the planet, but I do know of Udara or The African berry as it's popularly called. It's also referred to as Agbalumo and Wanu is some certain places in Nigeria.
It's a brown-orange coloured fruit who's taste varies from being extremely sour to extremely sweet. I'm not sure if it's found anywhere else in the world but I can tell you that it's definitely something that I bet alot of people haven't heard of.
It's eaten by opening it up and eating the fleshy parts of on the back of the skin. It's quite small in nature, probably around the same size as a tangerine but the seeds inside are pretty big and you can suck on them until you get to the hard exterior of the seed.
I recommend that if anyone reading this ever comes to Nigeria, they should make sure they try Udara, they'll never forget the taste.
Well, having lived in Asia for quite sometime now, it is my knowledge that the delicious fruit of Rambutah, i think commonly in south east Asian countries is not common in my Continent of Africa, or specifically in east Africa where i hail from.