If you follow indie video games at all you've probably heard of Minecraft, but it can be hard to figure out exactly what it is without some further research or actually playing the game. So what is it?
It's a giant tub of Legos. With monsters.
Each single player game of Minecraft takes place in a randomly created world full of mountains, hills, trees, beaches, oceans, lakes, trees, and other objects, all constructed from blocks of basic materials (even diamonds). Using various tools, you can cut, mine, harvest or break these objects, collect the blocks, then use them to build new objects. You can also smelt some objects using a furnace to make different blocks or use a crafting bench to combine blocks into new objects (like tools). There are also multi-player servers, which allow many people to cooperate on world-building.
So what can you build? Well, anything. In addition to the basic building blocks there's water and lava, which flows and moves as you would expect. There are trees, flowers, cactus and wheat, so you can create gardens, forests, or deserts. There's also a magical substance called redstone, which allows you to build powered circuits and devices. There are musical note blocks that play when you hit or power them, a new feature that people have already gone nuts with.
If this sounds like it might be your kind of entertainment, read on and I'll get into the basics of how the game works and give you a brief tutorial on how to survive your first night.
First things first, you need to know how to move, and how to gather stuff. Moving uses the standard WASD keys for move direction combined with mouse movement for turning. Simple enough. Gathering is pretty easy too, just get close to something, point at it, and click and hold the left mouse button. You'll start hitting it with whatever you have in your hands. Note the hold in that sentence. A lot of people are frustrated because they try to repeatedly click. That doesn't work. Once you've gathered some stuff it will appear in your inventor (the "I" key). The bottom row of your inventory matches up to your action bar on the screen, and you can place items in this area to use them. Tools make gathering more efficient, picks for rocks, shovels for dirt and sand, axes for wood, etc. Use them just as you would for gathering, hold the left mouse button. To place blocks or other items, put them in your action bar, select the proper slot (using the mouse wheel or the number keys), then right-click them into place. Right-clicking works for using things like doors and switches that have been placed in the environment too.
When you start a game of Minecraft, at least in single player mode, your avatar appears on a beach somewhere in a randomly generated world at sunrise. You have nothing, a situation you'll need to solve pretty quickly to survive the coming night. Monsters come out at night, so you want a safe place to spend the it, and some light. The recent version 1.2 beta patch made getting started a lot easier because you can make everything you need with a few trees worth of wood and a some cobblestones.
The first thing you may want to do is mark where you're standing. This is your spawn point, and you'll reappear here (minus what you were carrying) when you die. It's a good thing to keep track of. Dig up a few blocks of sand and make a pile of three or four blocks so you can spot it again.
Next, find a nearby tree and start gathering wood. It'll take several whacks to get each log so keep at it. You'll want ten or so logs at least. Once you have them, open your inventory and take note of the section labeled crafting. Pop your pile of logs into one of the crafting squares and note that logs produce planks. That's good, cause planks are useful. Go ahead and make planks by left-clicking on the plank pile, keeping two or three logs in reserve.
With some planks in hand we'll want to make a few tools, and to do that we'll need a workbench. Go back to the crafting area and place one plank (not log) in each of the four squares. Grab the workbench produced and put it on your action bar. Place it on the ground nearby with a right-click, then right-click on the workbench itself in the world. Better crafting!
We'll need a couple handles, so put a couple planks in two squares, one above the other. This makes sticks. Next put a stick in the middle square of the workbench and the one directly below it, then take planks and put them in a line, three across, the top of the area. Instant pick-axe! You can also make shovels, axes and hoes this way by rearranging the planks. Replacing the planks with better materials (stone, iron, gold, diamond) makes more durable items. If you have wood to spare, go ahead and make an axe and shovel. Hoes can wait. Gather your workbench up (left press and hold until it breaks) and move on.
OK, now you have some tools, so you can focus on the two things you REALLY need. Shelter and a light source. Look around for a stone outcropping (gray, usually on hillsides) and start digging. If you happen across some coal, dig that up too. You'll want to dig sideways into the hill making a two block high by one wide tunnel at least two or three blocks deep. Once you're in that far, widen out the area a bit and place your workbench in a corner. This will be your quick and dirty safe base.
Time to make a furnace. Open the bench and put a cobblestone in each square except the center. Grab the furnace, place it near the workbench, and right-click it. It's a little different from the workbench. The two squares on the left are fuel (the lower square) and what you're smelting (the upper square). The right square is where the results are deposited. Smelting is slow and night is probably coming, so let's get some charcoal made for torches. Put a couple planks in the lower area and place the logs you kept aside in the upper. They'll slowly burn and become charcoal.
While they're cooking, you can close the furnace and do something else, the smelting process will continue. if you have spare planks, you can make a door on the workbench by placing them in two side by side columns three high. Go outside and place your door on the outermost opening of your entry tunnel. Remember right-click opens and closes the door. Don't forget to close it at night!
The last thing you'll want is light, because night (and tunnels) are dark, and monsters spawn in the dark. Grab your charcoal from the furnace and open the workbench again. Place a stick in a lower square then the charcoal (or coal if you found some), right above it. Torches! Make as many as you can, then close the bench and stick a few in the walls and outside if it's not yet night. Torches burn forever so give yourself some good light.
By now night is probably coming, so close the door and settle in to wait it out. Now's a good time to make a sword, a few more tools, and perhaps start digging further into the hill to expand your base. When the sun rises most (but not all) the monsters will burn in the light. When you leave your shelter watch out for angry spiders and creepers which will stick around after the sun comes up. Most monsters just hit you and do damage, but creepers explode in a suicidal blast that damages both you and nearby blocks, so if you're being chased by one run away from your structures!
So that's Minecraft. If you want to see more about the game, check out the main site or this wiki for more details. Happy digging!