This is an Amish tradition. His name is Hermann and he is made for friendship. You can make the starter batch then keep him alive until he is ready to share, making a delicious cake with your part of him.
Start the mix during the meeting with instructions to take home - younger kids will need help and supervision at home but will have fun feeding Herman, watching him grow and sharing him with friends. Older kids can keep track and see how far Herman travels!
At the end of 10 days there should be cake! For variations on the final cake see: http://www.hermanthegermanfriendshipcake.com/