Minecraft is a block-building game that's lego-esque. Except there's only 2 sizes of blocks currently. You can build what you want whenever you want. You can build castles, rocket ships, pixal art, and more! The limit is your imagination.
Simply follow all steps and you can get Minecraft for free!
Notch is the indie developer of Minecraft, he first made minecraft as a 'clone' of infiniminer, but now it's evolved into a whole 'nother game. He's made Minecraft his soul project, but there are side projects he's worked on that are quite high quality.