Since getting back from my trip to Oshkosh last week I haven't been playing much of Blizzard's fine products. No Warcraft. Precious little Starcraft 2. Why? Because I'm obsessed with Minecraft.
Minecraft is a goofy little open world building game. The core engine is managing a 3d world made up of little cubes: dirt cubes, rock cubes, tree cubes, stone cubes, water cubes, etc. Your avatar walks around the world, smashing cubes and dropping new ones to create things. And oh, what things you can build: log flumes, underwater domes, all sorts of beautiful and silly stuff.
It's a one-man indie project that's been burbling along for awhile. Recently the game turned a corner. One, he put enough dynamics in the world to make it interesting. Two, he enabled multiplayer. It's a great social experience playing in a giant world edited by you and a few friends. Mainstream gaming is noticing: the Team Fortress group likes it, so does Bethesda (of Morrowind fame), and there's a good writeup over at Rock, Paper, Shotgun.
What I like best about the game is that it's a simple creative game, very relaxing, with no significant competition or conflict. Well, there is a competitive survival mode with dangerous NPCs wandering around, but I enjoy the game more in the creative multiplayer mode. Surprisingly satisfying spending hours digging through stone, creating beautiful mood lighting, playing with lava flows and building elaborate castles.
There's not enough creative games out there these days. I love games like Spore, SimCity, Starcraft, Civilization mostly for the building phase, the creative urge. But to make those "real games" they always end up with some conflict, some need to fight another person or the environment, and that part I never enjoy as much. (Related: I keep losing Starcraft matches because I just don't want to build an army. Make love, not war!). Minecraft is unabashedly creative and really fun for it. The closest analogy I can think of is Second Life, only Minecraft's way simpler and there's no sex.
You can try out the game real quick in this free browser hosted version. That will give you a feel for the voxel engine and the basic design. The free version is older, single player, and doesn't have a lot of what I enjoy about the game, in particular it's actually more fun to play with resource scarcity (and of course, multiplayer). But if you like what you see go ahead and register, consider ponying up the 10€ for a full account. You won't regret it.
Docs are thin, btw, but the Minecraft wiki is pretty good. The crafting recipe page is indispensable.