now i know your not much for mini games but seeing you have the arena and the parkour i figured this would be a perfect addition.
2Chill created the game and Nysic and baron helped a little with the command blocks.
so you start in a room where you get your stick. then you walk to the pp and it tps you to the board the players go around hitting each other with the stick till every one is knocked off. the stick is optional, it has a knockback 2 enchantment. each player in the arena has jump boost, resistance v(so no dmg is taken)there should be a warning letting people know to remove there Armor. the attached url is a download link if the link does not work i have also uploaded it to player chat on ts. rules are simple to fall off.
te idea is that it would be above spawn so that when they fall it wold take them a little time to get back in.