Not a movie suggestion, but can you get to some diverse neighborhoods and play in their playgrounds? We are fortunate that we live in a very diverse area and my children really play with every imaginable type of child with regard to race, religion, ses, family composition (gay, blended, single parent families, for ex). If you could somehow visit a more diverse area, I think there is no substitution for actually just getting to know different people. Otherwise, there are some good suggestions here. I particularly recommend Doc McStuffins. My DS8 still likes to watch it (but he will deny it in public).