Free Rice is a review game online. It presents a word and then gives four possible definitions. In the past, I’ve used the English version as a bellringer activity, letting the kids play as they come in and letting classes compete against each other. It helps with derivatives.
For each correct answer, ten grains of rice are donated “through the World Food Programme.”
I just found out from @quinnkl that Latin vocabulary has been refined and expanded. Watch out, though, since the principal parts of verbs are in a nonstandard order.