PlayPumps: One of the best ideas I've seen in years
Clean drinking water in sub-Saharan Africa is sometimes available only about a hundred feet underground. Even if someone drilled a hole, the rural communities often cannot afford the fuel to run the pumps to bring up the water.
So, the idea here is to install a pump disguised as a merry-go-round. The more children play on the merry-go-round, the more water is brought up to the surface. This invention especially benefits young girls who are often sent to fetch a day's water from iffy sources at great distances.
For people that say this won't work...they obviously haven't spent an afternoon at a playground watching kids play.