Another route: The Arduino chip can be purchased in a starter kit that comes with simple programs that can be modified as a way to start understanding code. It's fun because it DOES things (can control lights or sounds or motors).

This one was pretty good (though a few of the parts were cheap and broke): http://www.amazon.com/Arduino-Ultim...424355902&sr=8-2&keywords=vilros+arduino

It's the availability of sample, modifiable code that made this workable for us.

I imagine Raspberry Pi is similar; I haven't investigated it.

My kids also like Lightbot, which teaches about algorithms through a game. http://lightbot.com/hocflash.html