A website that almost always come through with great materials is the BBC. The network features interactive and informative games that captivate students' interests.
The two most recent that I have used are games that allow students to build a pyramid and mummify someone. I have students work on this games as a class to build team work and ensure that everyone is understanding the material and on task.
After these two games, my students will never forget that one shouldn't build a pyramid too close to a river (flooding) and that ancient Egyptian embalmers removed the brain from the.....
I don't want to spoil it for you. Play the game!