I decided to teach my niece how to program at the age of 10 as well. She had already just naturally gotten the hang of the computer since she was about 6 (though I had to reverse the mouse buttons because originally her small hands couldn't left click). At 10 years old she was already telling my sister-in-law how to do things, was a near master of google-fu and had all the game sites she liked bookmarked. I wanted to show her what else was possible, without it seeming 'sciencey' (apparently that is the new equivalent of 'nerdy').

I knew her weakness was video games - so I got her using DS Game Maker (http://dsgamemaker.com/) which allows you to to create games for your Nintendo DS. I had already set her up with a flash cart, so getting the games on there was a breeze. She started off with some real simple things, but as she learned how to do more and more (with some help from me on getting jump 'physics' going in Dynamic BASIC) and she eventually had a little game with her dog as the star in a 30 room game that each had puzzles to solve.

It's amazing what someone so young can accomplish - sadly her interest has dwindled and she is now on track to become a fashion designer. We shall see ;)