What are some fun games to play on horses?

I go to horse summer camp and we do loads of stuff! "mother may I..." "red light, green light" "turtle races" or slow races. you can do polo, soccer where you lead youre horse to a soccer ball and have them kick it, or just ride side by side with someone holding a long ribbon between you two and you have to stay next to each other so the ribbion wont break. shorten it for a challenge. Egg and spoon contest, or a command class. Maybe try a hack, or equitation class with a group of girls too.