Use a mirror (the kind with a handle) Put a neckerchief around the handle and a Cub Scout hat on the top.
Try not to obscure the view too much. Call all of the Cub Scouts forward to look at themselves in the mirror. After they have all had a look, have them stay upfront and ask the question, "Can you imagine these boys as Boy Scouts or even Eagle Scouts? That is our goal for them is it yours?