This site has a vocabulary game. A word is given and you must choose its synonym from a list of 4 choices. For each correct answer, 20 grains of rice are donated to the UN World Food Program.

I don’t know if it’s legit but at the very least it will help you improve your vocabulary so yeah, it’s worth a try. 2,260 grains later, I am trying to beat my personal best of 43!