Readers may remember BitQuest, as covered here on CCN. The Minecraft server uses Bitcoin for its economic component, and the results are fantastic efforts from those wishing to earn Bitcoin. They even had an architecture contest recently.
A group of players recently decided to take the market component of the Minecraft server to a new level by creating a market that would be supply and demand responsive. Players were able to purchase in-game currency using bitcoins and then buy blocks. Each in-game emerald is worth a bit, or a millionth of a Bitcoin.
Some blocks are more valuable than others, but at present the average price of a block is about 23 bits. The most valuable in-game block is quartz because it is the hardest to find. Players can trade their blocks in for emeralds, which are worth bits, and then they can take these emeralds and cash out of the game if they like. Or they can use them