That is an interesting site. It is a “non-profit website run by the United Nations World Food Program.” And it has two goals: 1. Provide education to everyone for free. 2. Help end world hunger by providing rice to hungry people for free.
So when you get right for each question provided by the site, they will donate 10 grains of rice for the hungry people in the world.
The subjects of the questions include: Art, Chemistry, English, Geography, Language Learning and Math. And they donated 12,255,121,230 grains of rice in 2007!
Try it now! http://www.freerice.com/index.php