Unfortunately, no one can be told what the Minecraft is. You have to see it for yourself....
couldn't resist.
it's a game where you can mine the ground.. use the stuff you mined (including the dirt and stone) and build buildings with. In single player survivor there are monsters that spawn at night and will kill you. You need to figure out what to do to defend yourself and build new and cool things. Survival multi-player is what is the big craze except that it's not yet complete. when it's all fully operational people will be riding minecarts between buildings, making swich networks of crappy simple electronic circuits to create automated subways .. of mine carts... building any building they can think of and generally participating in a community of creativity. It actually is kinda cool to travel around and see the stuff others built. When a server is rocking with 20+ people it's quite the show of things being built by groups etc etc.