I came across the Free Rice site on two different services that recommend websites, and it's certainly worth a visit. The deal is that the site will donate 20 grains of rice for every vocabulary word you get right. It's multiple choice. Now 20 grains of rice doesn't sound like much, but with all their visitors, Free Rice has donated 32,924,953,370 grains of rice so far. If you miss a word, they'll ask you again after a while.
