Dwarf Fortress.
Google it or something; I am far too busy playing Dwarf Fortress to talk about Dwarf Fortress.
It's a glacially paced (sometimes literally) game about economics, geology and agriculture.
"Press [ENTER] to create world"
Seriously though, the scope and scale of this game are preposterous. You can randomly generate a planet, and then open it's history books and look up every person who ever lived there.
Mjolnon Carveskull was a female dwarf, and a worshiper of Emnon Giantstone, a god who appeared in the form of an elf, until he was killed by the gblin hero Glin Splinterrot, in the year 67. Glin worked for the Purple Shadows, and evil force that built several Dark towersand temples, and plagues the forces of light to this day. I hope they don't attack my city, as their army is probably quite vast, if they have more than one Dark Tower.
For those of you who don't want to have your eyeballs seared out of your skull, by horrible, blinking, multi-colored E-ASCII graphics, alternate tilesets are available from the online DF help wiki. I wish I knew that sooner; my eyes hurt.
This game is free to download, and play. Full version. No joke. Google it.
It is also really, really slow. The world will usually be about year 250 years old. when you launch your first expedition. The world usually ends around year 1150. I've managed to keep a colony alive for almost 1 game year, over the past 2 days. The apocalypse is not an immediate concern, but it's coming. It is coming!
Did I mention this game is slow? You might want to bring a book. The game pauses whenever you open the help or select a sub-menu, so tinkering unnecessarily will slow things down. Once you get everything straitened out, I think a month passes in about an hour.
--But there's always one last tweak you can make that would make the whole thing more efficient.
If your dwarves are wasting time you want them to work more efficiently, but while you're making them more efficient, nothing gets done at all. It's really hard to just let your city run, so your careful planning actually gets carried out.
I really do recommend that you not allow yourself to become distracted while playing. I walked away for less than a minute, but when I came back, one of my Dwarfs had mistaken himself for Steve Irwin, and died in a tragic Alligator Wrestling accident. We dug him a very modest tomb, since he was our best miner, and we didn't have the labor to spare.
They don't normally act that stupid, but if you configure a character's task list just wrong, strange chemistry can occur.
The object of the game is to do whatever you feel like. Keeping your dwarves alive, sane and prosperous is generally recommended, but if the city is invaded by elves, or seized from below by an army of orcs led by a balrog, or turns out to be built on top of the tomb of an Elder Evil, that's actually kind of okay.
If you abandon your fortress, or simply run out of dwarves, you can send a new expedition or even send in a lone, super powered adventurer to fight the monsters and reclaim the halls for Dwarfdom.
Moria belongs to the Dwarves!
Strike the Earth!