There are various ways to procrastinate--but how many allow you to donate food and learn vocabulary at the same time?
FreeRice is a website with vocabulary games, and for every word guessed correctly, 20 grains of rice are donated through the UN world food program!
Works well as a party game (well, I think it does at least)
*edit: you can change subjects to spanish, german vocabulary, art history, pre-algebraic math...among other things. TRY IT!