Buy tickets to the local zoo, aquarium, botanic garden, or other fun activity. Donate the tickets to your local social services for foster families to attend. Attend with them. Set up a picnic at the local park.
May 10th is Mother's Day! Don't forget to do something nice for the foster mother's you know. Foster children might like to make a little card. Pamper the foster mother in your life whether she is YOUR foster mom, your spouse, or perhaps a relation or friend.