Minecraft is a first-person fighter/sandbox construction game created by Mojang AB.
When I first showed some of my friends Minecraft their first impressions were along the lines of "All you do is place blocks in some world with crappy textures". Almost all of those friends now own the game.
Yes, the game is all about placing blocks, yes the textures are low resolution (16x16px infact), but it grows on you quickly.
What you build is limited purely by your imagination (and time). In a randomly generated terrain that is 8 times the size of earth there is no shortage of space to build in nor resources. Notch has some awesome terrain generation algorithms that can produce stunning mountains forests and other beautiful vistas, despite the fact that they are made up from 1 meter high blocks.
I'll say this:
If you don't already own Minecraft, give it a go - play it at a friends place or something and you will quickly see how fun it can be.
A friend of mine asks me what Minecraft is about, and in reply I say, "You're a person who appears in the middle of nowhere in a random map, where you survive by taking different types of minerals, ores, and items to build and survive. In the night time, there are zombies, skeletons, giant spiders and green stalking things that explode." My friend gave me a quizzical look, and simply said, "That sounds lame."
What I am trying to get through is that Minecraft is just too hard to explain with words or with pictures. The first step of introducing the game is what stumbles and stops new players from playing. The fact that there is no definite aim of the game also puts off new players. The game requires the player to be creative. Unless they try the game themselves, they will never understand the extremely engaging gameplay of building structures, exploring caves and unknown lands, fighting mobs, and finding rare minerals and ores. The sheer joy when you find your first diamond vein after all the hard work mining is something not many games can give you.
Even with the game's appearance as somewhat cartoony and childing, exploring caves in the dark is a terrifying ordeal. When the only two things you have is an almost broken wooden sword and that fact that you are compeletely, and I mean COMPLETELY alone in this world, and the only thing proving that humans did exist once is that there are zombies, you get the sense of isolation which is sometimes hard to bear.
What is shocking to remember is that I only described the singleplayer. Multiplayer has all of this with the interaction of others and much more. This game is still in the alpha stages, but it feels that items and the different uses of objects are made to a near polished state. If there is a limit to how much I recommend a game, I have passed the limit a long time ago. absolutely perfect this game will be when it's a fully released. This game is only 10 Euros. Seriously, buy it.