Comment Kodu! (Score 1) 246
Kodu! Free for PC, cheap for Xbox. Build a game and it's environment using programming concepts without typing. Great for teaching "if this then that" logic, and hugely fun, which is great for keeping kids engaged.
http://research.microsoft.com/apps/mobile/showpage.aspx?page=/en-us/projects/kodu/
Also take a look on YouTube for a slew of games people have built with it.