Mesa Survival is exactly what you'd think: Survival in a mesa biome. You'll need to find resources such as sugarcane, saplings and animals in hidden locations in the map. You can find villagers and even bats! The map also includes some traps. It's 128x128 and was created using Worldpainter! On planetminecraft, it has over a thousand downloads. Compatible with pretty much every version above 1.7.2, including snapshots!
Have fun! No seriously- That's the only rule. Do you want to make it into your own custom map and upload that to the forums? Sure. Go ahead. Perhaps build an entire different island next to it? You'd like to hack in items because you feel like they should've been in the map? Do it! However, if you really want to have a rule: Don't leave the map.