Quiz Hub is a fun K-12 online interactive learning center that features iPad-compatible educational quiz games for English language arts, French, German, Spanish, math, geography, history, earth science, biology, chemistry, and physics.
This is a website that allows you to pick a subject and complete questions to donate 10 grains of rice for each correctly answered questions through the World Food Programme. Learning and Donating all in one!
This is a really cool site that has online social studies games. There are games that help you with memorization of maps and flags from all over the world.