Its a free ascii fort building god game in a randomly generated world... It looks kinda poor but it has the most depth iv ever seen in a game...
http://www.bay12games.com/dwarves/features.html
The standard version looks like crap but u can download modded games with gfx packs...
i.e. http://dffd.wimbli.com/file.php?id=3113
U will need to follow a guide for the first few hours and the game will generally piss u off until u figure it out... Ive only finally figured it out myself recently and its went straight into my top 3 favourite games list...