Equipment: one signal flag for each group, improvised from a neckerchief tied to a stick, four feet long, OR one flashlight or blinker for each group.
Groups line up in a relay formation. On the word "Go," the first player from each group runs up to the flag or blinker and sends Morse letter "A", races back to touch off the next player, who runs up, sends "B", returns, and so on until all letters of the alphabet have been sent. The first group to finish with all letters correct is declared the winner.
Variation: Have each player, in turn, send one word from an eight-word message tacked to the opposite wall.