Below is my TnTRun map. I used World Edit you make it. If you do not know how tntrun works, I will explain.

*Requirements*

-TnTRun Map
-Players
-TnTRun plugin (a plugin that makes every sand or gravel block a player steps on disappear)

When you get enough players, the game will start. After a few seconds of delay, every block a player touches will vanish. This will continue until every player but one is has fallen into the void. There are multi layers, so you aren't out if you fall down right away. Just keep running.

My map is slightly different, but can be corrected if it does not work properly.

There are 3 levels, and each level is roughly 44 blocks wide and 132 blocks long. You can shorten this with world edit if this is too long for your liking.

Every 44 blocks in each level traveling west to east, the ground drops 1 block, which means coming back (east to west) will be harder. 
e.g.
1st. Level ------........._____
2nd. Level -----........._____
3rd. Level ------........._____
VOID 000000000000000000

Credits: iEndSkelOpPerMen, WereWyrm, BenDR