Starting with only 1 block in the world - a chest containing a sapling, ice, a lava bucket and grass - your objective is to aquire as many different blocks and items as possible, using any means possible, including use of bugs/glitches. The only things you can't do are things that potentially give you access to every block and item, such as:
Going into creative mode
Branching out until you hit the mainland
Editing crafting/smelting/brewing recipies
Using a world editor to create/delete/move chunks
Using an NBT editor to edit mob drops, villager trades etc.
Using a Minecraft version before 1.2.1 (a normal world is generated instead of an empty one)
This map is all about thinking outside the box.
For example, your first challenge will be to get wood from your sapling. If you don't want to wait several hours for it to grow, what can you do (within the rules)?
Answer: Increase the tickspeed of the game
If you're creative enough, you can get pretty much every block and item in singleplayer!
While this world works in any Minecraft version from 1.2.1, you won't be able to shift-place blocks next to chests before Minecraft v1.4.6. And switching between Minecraft versions may cause problems like items disappearing from chests and not being able to respawn on the "island".