Today in 2006, one of the most complicated indie games ever made first hit alpha. Dwarf Fortress had already been in development for 4 years when it first hit the internet, and this Freeware classic is still actively in development. The big thing with this game, in a nutshell, is that it doesn't have any real graphics and its mechanics are detailed to the point of near absurdity.
If you are familiar with Dwarf Fortress you already know what I mean. If you don't, let me tell you some features that exist in this ascii art game. Dwarf Fortress contains game mechanics involving: randomized world generation, NPC personality systems, Liquid physics, an XYZ axis system, Geology, various forms of agriculture, military simulation, and I am barely scraping the surface. This game is nuts and you will die a lot.
Maybe you should try it out and tell us what happens?