free rice
So, here's something cool that I've discovered recently. You like words, you like feeding the hungry, you like .. rice. Click on this site, and it'll ask you a vocabulary word (not unlike ye olde SATs). For each question you get right, their sponsors (who pay for the relatively non-obtrusive adds at the bottom of the page) donate money to buy 10 grains of rice. Which isn't much, but it adds up quickly.
The rice is distributed by the United Nations World Food Program.
The vocab questions have 50 different levels, ... get three in a row right, and it bumps you up a level, get one wrong and it bumps you down a level. This means that it'll keep you challenged (unless your vocabulary is good enough to exceed their system) AND that the amount of rice you end up "earning" isn't linked to how good your vocabulary is, but rather to how long you've been playing.
I'd say that's a pretty good deal. Enjoy.