I need some Multiplayer Minecraft ideas please?

Okay me and my Cousin are going to play minecraft Together and we ar really competitive so I was wondering if any one has any good Ideas
TEN POINTS TO THE BEST ONE!

Make an arena and fight in it.

Minecraft Hunger Games.

Create boobies and fap to it.

There's super smash bros map you can download, it's pretty fun. Pick a mob and fight as it. Up to 4 players if 2 others want to join

Get all the materials used for fighting and you guys can each have some and you start of away from each other, make buildings that you can shoot from

Some ideas: http://www.minecraftbuildinginc.com/minecraft-building-ideas-100/