Has anybody tried using Grimm as a way to introduce real children (age range 10 -13) to rpg games? I have a couple of younger newphews somewhat interested in rpgs.

It is a fairly dark setting to bring kids into, but with their Vampire novels, and Harry Potter fighting soul sucking demons, they may well be prepared for that sort of thing.  Typically faerie tales have something of a "coming of age" theme, which would be appropriate for your players.

I usually recommend finding a copy of TOON for a young group's first foray into gaming - as it allows them to go nuts and just have fune, not even having to worry too much about death, since it only takes you out of the game for a few minutes.

My nieces (ages 7 & 11) have been into rpging. I have introduced them to Grimm and actually incorporated the world of Spiderwick into my games. Shouldn't be that hard to introduce them to it. Just use discretion as far as some of the underlying motif's that are found within the Grimm lands. That is one thing I LOVE about the game is you can go for an R rated game depending on the group to a PG and even a G rated game if need be. The system is just glorious.

 Thanks for the imput. I'll have to give it a try in about at about a pg rating.