This is fun! Check out your word power and give free rice to the world's hungry via the United Nations. I got four words wrong (one of their definitions was incorrect) out of 104 words, so I donated 1000 grains of rice to the project. Mind you, some of the words are really hard and I had to guess using etymology. My "vocabulary level" went up to 50 (the top level) at one point, but occasionally dropped down to 47. Apparently it is rare to go above 48. Woohoo!
The only problem with it is, that there is no stopping point, it just goes on for ever - potentially addictive.