The Ultimate Guide to Eating Paleo (Infographic) | Greatist
Take a look at that link. It is from mark's weeknd link love a while back. It is a pretty good and quick intro (as well as kid friendly) to primal/paleo way of eating.
Also give a look at the CrossFit Kids nutrition section on CrossFit.com mainsite. That might be something your kids could take a quick llok at.