Little King's Story is a good any-age introduction to RPGs. Multiple layers to the story keep you busy but with the simple gamestyle, things don't get too complicated. Tha map function could use some work and precise aiming takes practice but you'll get a few hours of fun out of this one. I recommend playing the game on Mute because the repetitive music and sound effects could drive you crazy.
This is one of the most charming and subtly disturbing games I have ever played. It looks vaguely like it ought to be a kids game, but considering that you're only focus is world domination (with a eugenics tinge) throughout, perhaps children shouldn't be allowed within 100 feet of it. The game's subtle sense of irony actually makes it a great deal more enjoyable to play than it would be otherwise, and the graphics, while rather poor, are in their own way quite charming. I gotta say, this is actually a pretty awesome game.
I have a 4 games out at a time Gamefly account and this one was one of the games my little brother put on the list. From the minute he got it he was playing nonstop. Looked a little kiddy for me but if u have a 12 year old at your house they'll love it!