I just finished talking with a colleague whose six year old loves minecraft and I remember talking with a twelve year old who was similarly obsessed - to the point of knowing the patch numbers and all the details. The community which grew organically around this game is incredible, and that kind of peer-to-peer promotion is priceless.
I have used twitch.tv for perusing games I am interested in as well as screening games for my niece and nephew, usually I send a link to my sister and ask if the game is acceptable and would her kids enjoy that.