|Try to keep a straight face!|
artwork by Larry Wright
Players are evenly divided into two groups and stand facing each other 3-4 feet apart. Opposite sides of the doubles alley is ideal. One of the groups is designated as the Hagoo side. One player from each side is chosen to walk slowly between the two groups from one end to the other. Each starts at opposite ends. They will pass each other in the middle. The players lining each side try to make the walking players smile/laugh as they walk through. Noises, gestures and faces may be made but no one can touch the two walkers in the middle. If either of the walkers smiles before they pass through the entire line, they join the Hagoo side. If they make it through without smiling, they join the other side. This is repeated until all players are in one of the two lines.
If this is not tennis-y enough for you, easy to add tennis-related options. Have the walkers balance a tennis ball on their racquets, or dribbling downs or ups as they pass by. Instead of trying to make them smile, you are trying to make them miss. Make sure players have plenty of room to pass safely. Remember, no touching of the walking players is permitted.