davesnider, My kids are 9 and 11. They've been interested in Dungeons and Dragons indirectly through me for years. I was worried it was a little too rule heavy for them, and instead started them on a Game Book (basically a choose your own adventure with state) called Legendary Kingdoms. It's meant to be single player, but you control four characters. I narrate.
We've had the best time playing through the story. Highly recommend as an intro to deeper gameplay for young kids.