With Minecraft, the wildly popular lo-fi sandbox game, you can explore maps, fight (or avoid) mobs, build automated contraptions, and design structures, by yourself or with friends.
Play like you want: You don't beat Minecraft -- there are no princesses to save, no armies to defeat, no obstacle courses to complete -- so you can spend your time as you wish. Collect raw materials, grow food, and craft items. Or explore to discover mansions, villages, and fortresses and enter different dimensions. Or fight mobs -- including zombies, skeletons, and dragons -- and even other players.
Single or multiplayer: You can create a single-player world to play alone, set up a world that you and others can play on a local network, or join a world (or create your own) hosted on a server, with dozens to hundreds of players.
Customize the game: When you start a new world, you pick your style of play, including Survival mode (where you collect resources, craft items, and work to stay alive) and Creative mode (where you can quickly spawn items, fly around, and spend your time building). And you can change the characteristics of your game through community-created mods: Add a map to track your travels, for example, or introduce new items and crafting recipes.
Create useful mechanisms: Using redstone, you can build automated devices, from lamps, passcode doors, and automated farms to Rube Goldberg machinery. Redstone acts a bit like an electrical circuit, letting you power items on and off to build surprisingly sophisticated devices.
Engaged community: The game is supported by a large and passionate community, running wikis, forums, YouTube channels, and Twitch streams. You can find everything from detailed explanations for building redstone devices to live streams of players running around bashing mobs.
A few unruly server communities: Joining a server community is a good way to learn about the game and participate in projects and events you could never take on alone. While many servers are well run with supportive and attentive admins and mods, some are more anarchic and not appropriate for everyone.
Modding not for the fearful: Minecraft doesn't have an easy mechanism for adding mods, and the effort can be frustrating. Modifying the game may require you to browse shady-looking websites, synchronize mod and game version numbers, install software your computer may warn you against, and dig through folders you probably shouldn't know about. The results, when done right, make the game much more fun but require skill and patience.
Minecraft's open-ended nature is a big part of why it is so fun to play. While picking the right server community or modifying the game may require patience, Minecraft is big enough to encompass a world of playing styles.