I've decided to make a Survival map based on the Minecraft Lego micro world set. I made the outer edges of the world open so you can do some of the challenges.
Challenges:
1) Build a bigger house
2) Make a Mob spawner
3) Expand the world/ island (Whatever you wanna call it)

Those are all of the challenges I can think of right now, if you guys can think of something tell me and i'll add it.
This is Version one of this map.