This was a game I did for the Great American Teach-In at my kid's elementary school. It took less than a week, the main things I wanted to show was you combined a little bit of math, a bit of science (gravity), a bit of art (animation) and other things kids learn in school to make programs in Computer Science, like games.
http://www.youtube.com/watch?v=vPk4u2Tx6YYI would take a webcam picture of a volunteer in the class and make them the "boss" to avoid at the end, plus I themed the game to have elements from their school (thats why all the coins spell 'pride' which is the name of their school).
Had a lot of fun with this, it has rekindled my interest in writing more games again ... so have a few ideas and I hope I can finish them this time around.