Game description from the official site:
“Minecraft is a game about breaking and placing blocks. At first, people built structures to protect against nocturnal monsters, but as the game grew players worked together to create wonderful, imaginative things.
It can also be about adventuring with friends or watching the sun rise over a blocky ocean. It’s pretty. Brave players battle terrible things in The Nether, which is more scary than pretty. You can also visit a land of mushrooms if it sounds more like your cup of tea.
You can buy Minecraft for PC/Mac. Minecraft: Pocket Edition is available for iOS and Android, and Minecraft: Xbox 360 Edition is available on the XBLA Marketplace. So far 14,116,681 people bought the PC/Mac version of the game. Phew.”
More info can be found on the official Minecraft site.