Minecraft is a sandbox game created by Markus Persson, a.k.a "Notch". It is inspired by many games, especially Infiniminer. It has over 400,000 registered players.
There are 6 modes:
Creative: makes you build anything you want, single-player and multiplayer
Survival: a very basic version of Indev, where you have to defend yourself from monsters
Indev: a version which added a number of new features, including crafting and more monsters
Infdev: same thing as Indev except this version added an infinite playing surface
Multiplayer is a part of Creative mode, which allows you to build with other players in servers.
Unfortunately, there are "griefers" that destroy creations including yours.
A survival multiplayer was created in August 2010, which allows players to play Indev with other players.
A typical Minecraft conversation when a griefer comes to a server:
coolguy10: supergriefer54674 is greifed my house!!!!1111
supergriefer54674 is banned!
Minecraft is a game written in Java created by Mojang AB in 2009. Minecraft has two current variants - Classic (which is free) and Beta (which you have to pay for).
In Beta, the main goal is to survive. At night, monsters spawn (but not in Peaceful mode) and attack you so you need to craft items and tools to help you survive. You also need to eat regularly.
Minecraft has gone through many development stages:
Classic - the oldest version. It is still playable and has multiplayer. In Classic, you have an infinite amount of blocks, no health, and no mobs.
Survival Test - Part of Classic, very basic compared to the Survival we play and know today.
Indev - Added a number of new features, including crafting, torches, and tools.
Infdev - Added the ability to have an infinite playing surface.
Alpha - Added biomes, nether, sneaking, and much more.
Beta - The current version of Minecraft. Added beds (which can skip the night), more mobs such as endermen and wolves (which can be tamed with bones and attack monsters), and many more.
Multiplayer is in both Classic and Beta, which allows, well, multiplayer, duhhhh
Girlfriend: Why aren't you spending much time with me, Greg?
Greg: SHUT UP AND GO AWAY, I'M PLAYING MINECRAFT