I'm sure this has come up here before, but just in case (And because I saw that ErfWorld thing), I figureed I'd tell people about this amazing free (Donations only) game.
http://dwarffortress.com/ fansite
http://dwarffortresswiki.net/index.php/Main_Page Wiki
http://www.bay12games.com/dwarves/ Developer page
Anyway, the game is in ASCII and just gets more and more complex..should be a huge slew of an update this year too. You play either as a commander/god of a new dwarf fortress or as an adventurer (Not much in the latter yet...although still fun, especially if you survive for a bit).
But instead of me failing at telling you about this game...go check out the old epic of
Boatmurdered
EDIT- There IS a steep learning curve (Why I put the wiki on here)- but once over the hump the game can bring all sorts of joy..especially as it gets better and more things will eventually (hopefully) be added.
Dwarf Fortress
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