I thought I would share this website that my family have got hooked on 
It is managed by the world food programme and for every question you get right, they donate 10 grains of rice to thrid world countries.
If you register on the site you can keep tally of how much rice you have donated and even create groups with friends so you can play each other 
Its a great way of getting some sneaky learning into your kids and there is now a range of subjects for them to answer questions on including english vocabulary and grammer, geography,langauegs science and more.
My kids watched the video showing how the aid programme works today and have now all pledged to donate at least 100 grains of rice every day before going onto their other games its called freerice.com