Lego Mindstorms (Score 1)

The Lego Mindstorm environment is excellent for showing how software can effect physical action in the real world. They have a graphical programming environment easily grasped by 7 years olds. A few point and click actions and you can change the behavior of an attached robot. And an "NQC" simple C text environment is available free. $200 for the box with 'Brick' computer.