I am working on a little side project, a Minecraft server that uses Bitcoin for the economy.
Its just launching, and there is a lot of work to be done, but there is also plenty of unclaimed land.
Server URL: coincraft.net
To deposit bitcoins do /deposit and you will be given a bitcoin address. Bitcoins show in game after one confirmation.
Plugins currently running: Factions, Essentials, Satoshis
I will be adding auctions, gambling, games and pretty much anything the community suggests.