Click on the link above to get to the site Free Rice.com.
This site is set up through the United Nations so that every correct answer from visitors to the site, contributes 10 free grains of rice to the United Nations World Food Programme. The "quizzes" (aren't really quizzes) but a great review for learning vocabulary, math, geography, even foreign languages!
Students love to see how many grains of rice they earn in a time period, and on a rainy weekend, some students keep going...without actually realizing that they not only are doing something good for the world, but maybe even learning some things!
Players can choose subjects and subject levels at the site.
It's a great "free time" activity at the computer for students and adults alike!