Dwarf Fortress

[Human No More]

I know Eltu and Thorinair play, but wonder if there are any others

It is a completely epic game, really open ended - you control a group of dwarves, initially only a few but it rapidly becomes a whole city's worth. You create a fortress, you can really do what you want, it's completely open ended, whether that's make a huge industry, or build some crazy megaproject, or just flood the map with magma

It can be fairly hard to learn, your first few fortresses WILL starve to death, get wiped out by goblins, get flooded, have your dwarves all go mad and kill each other... but that's all part of the 'fun' and learning experience - once you know the game, it get simpler and you can soon start making actual successful fortresses

Official site: Bay 12 Games: Dwarf Fortress
Wiki (spoilers. mostly clearly marked): Dwarf Fortress Wiki

More about the game (hidden spoilers): Dwarf Fortress - Television Tropes & Idioms

One recommendation I have is to use a tileset, greatly improves the graphics and makes them much more readable over the default ASCII ones.
the best tileset is here: http://mayday.w.staszic.waw.pl/df.php - just download the latest version which is a copy of DF with it installed.

A few things for starting out:
DF2010:Quickstart guide - Dwarf Fortress Wiki
Tutorials - Dwarf Fortress Wiki
Game Basics - Dwarf Fortress Wiki

Of course, if you have any questions, ask away
This game really is addictive once you've learned it...

[GP-5]

Add me to the list. How can I not love a game that includes communist dwarfs and burning babys (who also have beards from birth).

I haven't played it much since the 2010 version was released since I found it way to buggy in the begining. I gues they've sorted that out by now. But yes, it's one of the most time consuming games I've ever played. Time just flyes out the window when you start it.
Now tell me... what do you think of the 2010 version and also... I want to hear about your megaprojects or simply awesome stuff you've done :3

[Human No More]

I haven't done much that ranks as truly epic... maybe the entrance hall that can drop goblins into magma , the obsidian farm (although everyone makes one of those), the towers (again, same), or the legendary adamantine statue (I decided it's a statue of Neytiri )
the 2010 version is great, would recommend it

[GP-5]

Going to post some stuff soon but until then..... enjoy these very true words.
http://i.imgur.com/mHXiz.png

[Thorinair]

Here, my fortress... Use the points on interest on the menu to the left.

Obsidian Halls - 64 Early Winter by Thorinair
(Notice the epic-ultra-awesome logically automated obsidian factory.)

EDIT: This is a newer map: Obsidian Halls - 65 Early Spring by Thorinair, but it doesn't have all the points of interests. You will have to navigate through it manually (look for the good old obsidian factory to see the process in progress.)