The average person in Sub-Saharan Africa uses 4 gallons of water a day*. That isn't even how much they would like to use if it flowed freely and cheaply through a tap, but how much is used. Y'see, only 56% of SS Africans have access to an "improved" water source within a kilometer of their home (World Bank, 2008). So 44% have to travel over half a mile, and in some cases much much more, to find water that may or may not be of good quality.
How do they do this? Mostly the women and children carry the water by hand, and mostly that means in 5-gallon, 40-pound drums balanced on their heads. This is hard work (try carrying two gallons of milk around with you on a lap around the store and think of doing 2-3 times that weight for up to 5 hours a day).
Well, at least two projects have addressed this by going back to that most basic of inventions: The Wheel. Why rectangular drums? Make them big round drums and they can be rolled, pushed, or pulled by rope and put much less strain on head, neck, shoulders, arms, and back. It makes the work safer and easier, and reduces the time because they aren't as burdened. One project is called Hippo Roller (left) and another is the Q Drum (right, hat tip Chris Blattman). Pres. Obama's stepmother is even seen supporting the initiatives.
* - I have to wonder if that includes South Africa in the estimate and what the difference is between the arid Sahel and the tropic regions: Africa is not a country.