Cell phones are popular in Africa. So are bikes. Africans are sad when their phone runs out of charge, because the landlines there suck. Discovery News is reporting that Nokia, the Finnish phone maker, has a device for recharging your phone by riding your bike.
The article describes it as being a fan that attaches to the bike, drawing power from the air resistance. 20 minutes of typical riding produces enough charge to power a simple device like a phone or music player for 40 minutes, which should prove a comforting companion to traveling Africans.
There is, of course, a physics catch to this, and that is that the energy doesn't just magically appear from nowhere. The fan would produce additional air resistance to riding at least in proportion to the amount of electricity produced. So it's not so much bike powered as African person powered. Still, being able to produce your own electricity in a country that usually has none is a pretty sweet deal.