I've been running a TerraFirmaCraft game with a friend for a while, and it would be pretty cool if more people got in on it. For those who don't know, TFC is a total overhaul for Minecraft that re-writes Survival in a much more difficult 'realistic mode' in which you have to keep in mind a lot more factors such as season, food decay, gravity (houses & caves can collapse), smelting conditions and a lot more.
I won't post the IP or anything because I don't want random people or griefers joining, but anyone who wants to try it should post below or add me on Steam (under McZealot).