Here's a thread about Dwarf Fortress, the game that's like NetHack combined with The Sims and more madness than you could shake a stick at. You manage a Dwarven Fortress populated by drunken, moody and moronic dwarves. You must mine out their living spaces, trade or war with neighboring peoples, build insanely complicated megaconstructions and dig ever deeper for wealth and glory. It's a little bit like Minecraft, being in perpetual beta and capable of simulating amazing things, except that it's for real gamers and not babies who need a 3D interface. It's all ASCII, just as God intended for PC games.
As in life, there is no way to win Dwarf Fortress, but countless ways to lose.
Here's a link to a more gentle version with graphics and a bunch of utilities already installed: http://www.bay12forums.com/smf/index.php?topic=59026.0