CK-12 - Interactive learning activities. All subjects! 

Bridge Builder—learn how to design and test bridges

iCivics—experience what it means to be part of a democracy

Making History: The Great War—WWI strategy game

MidWorld Online—learn French or Spanish while completing conquests

Mission US--students role play the American Revolution or the Civil War

Past/Present—life as an American immigrant in the early 1900’s

SimCity—learn how to run a city

SimTower—learn how to run a high-rise

Coffee Shop—run a coffee shop business

Electrocity—learn how electricity contributes to the growth of communities

Lemonade Stand—run a lemonade stand business

Life (Insurance)—manage your life and see why insurance is important

Science simulations—lots of choices for 2nd-8th graders