Alright so, I've been watching a group of youtubers, and they play a game in Minecraft called Ultra Hardcore, it's a free for all competition, or it could be done in teams, up to 4 per.
The point of this gamemode is to be the last man standing, sorta like Survival Games. The hitch is that you don't regenerate health by normal means (having a full hunger bar), you'll need to make a golden apple to get health, or you could take a huge risk by going to the nether and getting the supplies for potions.
http://dev.bukkit.org/bukkit-mods/ultra-hardcore/ Check this out if you'd like to read more into the mod.
there's 2 ways to make the map, using the commands the mod gives, or using MC to make a bedrock wall around the area, which spans from 1000 to -1000 x and z (2k by 2k) where 0,0 is the very center of the map.
Here's a trailer featuring people who started UHC:
https://www.youtube.com/watch?v=KrE9zogQhHE
Basic rules:
1. No branch mining/strip mining, you can stairway down to try and find a cave, or dig to try and find a cave(10-20 blocks max)
2. If you die don't reveal in chat to how the person killed you or what they have.
3. You die you are out, no staying in the server.