This is my idea for a minigame. You have about a minute or so to think of where the command block that isn't see able for the players is. You have to be within 5 blocks (could be more, could be less) to win, as for the others, let's just say they'll be hot after losing. The download contains 3 of the same arena but with a different safe point and a notepad with cheats as to where in the arena the safe points are. This might not be the best idea for a minigame but I think it's still pretty cool.

Note:
The emerald named "I Have an Emerald" that you start out with is just a joke I came up with. Basically I used to sometimes hold an emerald in my hand on a survival with my brother and start hitting him shouting, "I HAVE AN EMERALD!"