http://www.freerice.com For every vocabulary question you get right, the website donates 10 grains of rice to the World Food Programme. The more you get right, the higher the difficulty becomes, and vice versa. I'm at level 37 with 890 grains. It could be a great way to motivate someone to study for SATs!
I they already have the rice, why not just give it to them anyway? Assholes... I wouldn't trust my ability to eat to the vocabulary of others.