Minecraft follow-up, Scrolls, to now be in closed alpha. Just like Minecraft, the game is will roll out one piece at a time, first in this testing phase, with more features to come after the official release. In the current alpha, players can build up their deck of scrolls and fight against an AI opponent, or play random matches in multiplayer.
It sounds basic, but Mojang wants to iron out the core gameplay before adding any more complexity. The closed alpha will use "quite a modest number" of players to begin with, and eventually grow into a full open beta.