This Game is meant for Cub Scouts.

Everyone sits in a circle. Leader says to maintain a serious expression unless you have caught the smile being tossed around.
The leader smiles, then wipes the smile from his face into his hand and tosses it to a scout in the circle, calling the scout's name as he does so. The "smile" catcher must put on the smile, wear it for a moment, then "wipe" it off and toss it to another scout, calling his name. The scout who does not wipe the smile completely off, or smiles out of turn, must stand up. Since smiling is contagious, the entire group will soon be standing... as well as smiling.