I made a small Battle area with some friends one time. I still have to put a bit more detail in it..

No rules; Make em up yourself, explore on your own or play with or against your friends! BUT don't play on "peaceful" difficulty!
No command blocks; If you want to play again, make a backup of this file!!
Not very much redstone; Only for the traps.

And Loot chests!!

The big tree in the middle hides a great treasure, get to it and beat your friends with it!

- Have fun ^^