I taught my 8 years old girl using JavaScript and we made a simple game (numbers falling from the top of the screen and you have to click them to make a number:

I taught my 8 years old girl using JavaScript and we made a simple game (numbers falling from the top of the screen and you have to click them to make a number: e.g. "3" and "4" because the number to make was "7"). It eventually became PopMath (which I reimplemented in ObjectiveC for the iPhone) but she understood the concept of loops, random number generation, collision with sides (so x coordinate had to be reversed) and event handling (function to get the user clicks). I also did the same with my son when he was 9, with another game where the player would need to use arrow keys to navigate a maze. Also in JavaScript because they can see the results right in the browser, can easily add graphics, and even sound effects. I think simple games are a great teaching tool.