Instead of the usual princess or dinosaur party, give your child the gift of giving. Instead of having gifts brought, have donations to the local animal shelter for the birthday boy/girl
to donate. It will not only teach the children the gift of giving, but you can often have someone come and talk about taking care of animals, how animals influence our lives, etc.
Maybe have a balloon artist make animals for the guest children to take home. It will be a learning experience for all...