From the BBC,
The two electrical engineering students from Nairobi University have been working on their own invention, which they are selling for 350 Kenyan shillings ($4.50) each, over the last few months during their university break.
Mr Katana explained it takes an hour of pedalling to fully charge a phone, about the same time it would if it were plugged into the mains electricity.
Yay for entrepreneurial spirit. Hat tip to the Roving Bandit.