I found this when I was supposed to stop hanging around clipmarks and actually do some work.

Go and click, for each time you click you test your knowledge and donate grains of rice to feed the hungry. How does this work.... the advertisers pay for the rice.. They are located in a banner at the bottom of the page. Fun, addictive and Educational and Altruistic* all at once. * see..I learned something

i kept playing until my vocab level went below 30. i ended up donating 1230 grains of rice. it was fun.

This is SO much fun! Just great. Thanks.