Playpumps

In many developing countries, children walk for miles to collect water - often before and sometimes instead of going to school. What should be play time becomes chore time while they carry out this vital task. Play Pumps International neatly addresses both these problems, with a novel design that combines a playground merry-go-round with a pump to draw water from underground and store it in a water tower where it can be drawn off as required. An added twist is the use of the sides of the water tank for advertising, generating revenue that can be used to fund maintenance of the system.

My son, who's 9, thinks this is the coolest thing - and wants to know whether they can also make one that's a see-saw. I think he has a point.