Three things which worked for me when I was a kid:

- Games - Pretty pictures - Music

Someone suggested python processing. This might be cool. Also, pygame can be fun. For games, you could introduce the kid to the game of Nim, learn a strategy to always win, and the kid can program the strategy. Make it a real game that someone might load up and play, with whatever graphics, sound, and experience the kid wants.

Having the computer be the blackjack dealer would be another option.