Bill Harris at Dubious Quality is a smart cookie, so it's interesting that he's raving about practically unknown PC game 'Dwarf Fortress', calling it 'one of the most complex and demanding games I've ever played'.

He commented of the title: "Think Space Rangers 2 came out nowhere? The graphics in this game are ASCII. In 2006, that qualifies as out of nowhere. It's in alpha (although it's already far more stable and complete than most commercial releases I've played this year). And it's free. It's also one of the most imaginative, multi-layered, detailed gaming worlds I've ever seen."

A good basic description is also provided: "In simple terms, when the game begins, you have a group of seven dwarves at the base of a mountain, and your goal is to survive. And to survive successfully, you'll have establish stable sources of food and create shelter. Each of your dwarves has abilities, and they can learn new ones, and you must use their skillsets to create a sustaining environment." There's are several follow-up posts on Bill's blog with more in-depth playtesting info.