I once saw people at my school on the computers who had a screen of multi-colored boxes. Then I realised they were playing a game. I asked them what they were playing when they replied 'Minecraft'. Then a moving square came and attacked them, and I asked what the hell that was meant to be. It was a cow. The graphics are indescripably horrifying, and the game play is making more boxes, then breaking some boxes, then making some more. I'd rather play a game that actually has the graphics and gameplay to call itself a game. Assassin's Creed. Oh yeah.
i think you just go to minecraft.net and register then play. its online right now, being in beta, but its a real game in developement so it would be sold when finished