My good friend directed me to the coolest website: Free Rice. You answer questions, and for every correct answer you get, they donate 10 grains of rice to the World Food Programme to help end world hunger. There is a running total so you can see how much rice you've donated in one session (or you have the option of keeping a running total).
This is a great site for homeschoolers. Kids (and adults!) can answer questions on art, chemistry, English grammar, vocabulary, geography, math and foreign languages. It's not only fun and educational, it's also a worthy cause! Check it out!