http://www.mathsnacks.com has games for teaching middle school maths.
Designed by new Mexico State University.
eg Youtube clip
http://www.youtube.com/watch?v=8D7QX5F5wWM&feature=related
www.sciencepirates.com has a 2 hour long game for middle school students to learn science.
eg. Youtube clip
http://www.youtube.com/watch?v=O8Ynuj7_8xM&feature=related
Then there is the Fight BAC (food safety) series in English and Spanish, eg