Minecraft is a first-person game where you build things from blocks. That's it. You mine blocks with the left mouse button, and place blocks you've mined with the right button. You can build just about anything. I've taken a fairly pedestrian approach, and am currently building a tower:
In retrospect, it was stupid of me not to take a "before" screenshot; that used to be a hill.
It's not just an endless game of Lego. At night, monsters spawn around you, so you have to build some kind of a shelter to not be eaten by the living dead or blown up by an exploding suicide cactus. To mine rock and other hard materials, you need tools, for which you need wood, both to make the tools and build a workbench to build the tools on. You can find ore, and smelt it into metals, but that requires a furnace. You get the picture. Here's a glimpse of the inside of my castle:
As you can see from the mess around it, I'm still in the process of removing the remnants of the hill and landscaping the whole place so it looks neater. I just finished the walkway to the smaller tower yesterday. When I say yesterday, I mean last night. The only exit from my tower is down the walkway and through the smaller tower, to confound the exploding cacti. I'm happy to say it's working! Here's a view down onto the walkway from the main tower.
Words cannot adequately describe what a fantastic game this is. It's like playing with Legos when you were a kid, only so much better. Minecraft has already sold over 600,000 copies, and it costs a measly 10 euros; there's a version on the site you can try for free. The website is here; there's no documentation yet, but that's no problem at all, as there's an exhaustive wiki. There's an excellent tutorial that will get you started.
Believe me when I say that my tower is a ridiculous little hovel compared to the things some people have made. It's simply amazing what you can put together in the game. I was still quite proud of myself when I finished the first proper story of my tower! I'll finish off with a picture of the sun rising, as seen through my east-facing panoramic window.
So if anyone's wondering where I am or what I'm doing, this is the answer. Minecraft. I love it.