We've had our decentralized blockchain/crypto game Townforge under development for quite some time at https://www.townforge.net. We offer pre-compiled binaries for Linux, Windows and Mac, while the game itself is fully open source and anybody can access the source at https://git.townforge.net.

It's maybe best characterized as a city-sim / RPG hybrid, with Minecraftian voxel mechanics coupled with text-based adventuring and player-driven emergent economy similar to MMOs such as EVE Online.

The crypto implementation is originally forked from Monero, but it has been obviously heavily modified. All the game actions go into the blockchain, and players earn in-game gold as mining rewards or make profit via in-game economy (e.g. subsidies for buildings or peer to peer markets).

Please do note that the game is in a testnet, so everything's temporary until we feel the game is ready for a mainnet launch.

We've got our own little ANN-thread going on here: https://bitcointalk.org/index.php?topic=5317101 though IRC's probably our main medium of communication (##townforge @ Freenode).