My friends, I have found the most wonderful, nerdy, and actually-almost-useful time waster.
You get the word’s meaning correct, they donate 10 grains of rice to the UN. Don’t ask me how it works – haven’t read the FAQ – and I choose not to think about the ins and outs of this. Because they’re words, man! And they want me to define them!!
I donated 1520 grains tonight. What I particularly like – and this is where my competitive side comes out – is that it records your vocab level, and if you get a word wrong you go down. The highest I got tonight was level 47.
Free rice love!
Randomly Yours, Alex 
I had a go. I made a little bit more rice than you, but only made it level 44. It says that hardly anyone gets past 48, so you must be doing well.