Spent some time on freerice.com this evening.
I tried the English Grammar and pretty much did all the questions and levels they had, but that only took me to 2000 grains of rice!
My brother Jiten helped out and donated 5120 grains of rice!!! In about an hour! He tried geography and math (he's a math whiz!) and did english vocabulary, which he said was a little tough : )
7120 grains of rice donated in just over an hour! Having too much fun giving back!