One of the best things you could give your kids for Christmas this year- if they don't already have it- is an understanding of the Zero Aggression Principle.
So, ZAP your kids.
How can you make the concept simple enough for kids (or the average statist) to understand?
Perhaps like this: "You shouldn't push or hit anyone who didn't start it. You shouldn't say you are going to hit them to make them do what you want. You shouldn't have someone else hit them for you. And you should keep your hands off their stuff."
I know that explanation misses some subtleties- saying they "shouldn't" instead of that they have no right to, for example- but as they get older you can adjust it to their level of understanding.
I know a few kids this gift of understanding would benefit a lot. And it would benefit those subjected to their presence just as much.
Oh, and if you think a little book might help them out, maybe Indy-Pindy is what you are looking for.