As with any proud parent, when your child is doing something good you want the world to know. I made a "Missionary Mom" button with my friend's daughter's picture. She is serving a LDS mission and her family is very proud. (So are her neighbors.) Along with proud parents are Missionaries living away from home. I put a family picture on this button along with the words, "My Family Loves Me". What's special about this button is the magnet on the back so that the missionary can hang this small reminder of home on their refrigerator and see it often.
Of course, this button could have a picture of your child playing their favorite sport or just smiling.