Personally, watching slideshow clips in the "Strangers Like Me" musical sequence in Disney's Tarzan always makes me think "Wow... I know a lot of shit." Because I can give at least a basic description of the things appearing in every single clip, and it gives me a hint of the scope of all the motley stuff I know that would be completely alien to me if I had grown up, say, in an isolated tribal village in Africa.
How much of it is actually useful is another matter, but there are certainly occasions where I find myself drawing on knowledge like, say, which is the country of origin of sumo wrestling, which I wouldn't predict in advance to be especially useful.
You have the Encyclopedic Knowledge merit from World of Darkness.
But, yeah, random knowledge has more uses than merely impressing people. However, please note that your African would have specialized knowledge and skills related to his own environment, not to mention cultural lore. He has probably memorized thousands of verses of poetry, for example.
From Julian Sanchez, a brilliant idea unlikely to be implemented: