What is the best game for hotel employees to play on their birthdays?

Props: a balloon and a rope.

Participants: two groups of confrontation (generally 3 ~ 7 people in each group)

Rules of the game: Before the game starts, pull the rope along the middle of the field (like a tennis net), and then both sides line up to head the ball. Whoever lands first will lose, and both sides will take turns to serve. Demonstrate the ability to cooperate and compete (note that you can only use your head, not other parts of your body).