So just behind Kentela's house, in the desert, I've opened up an area where people can battle each other to their hearts contents. Just remember that blowing up the area with TNT or creeper collateral (or otherwise destroying the area) should be avoided, so we can keep using it for some time. There's no pressure in going into the area, and it's marked up pretty well as long as you're entering from the surface with warning signs. If you're within this area, anyone else that is within the area is allowed to attack you.
Just remember, attacking someone who is outside the area while inside the area is not allowed, and vice versa. Both players must be inside the border.
So if you find yourself in need of a battle to the death, this is the place to do it. Oh, and all items lost within the area belongs to the first person to pick it up. That way, you can both put up wagers in a fair fight if you desire.
How much does a polar bear weigh?
Enough to break the ice.