This server is called WesterCraft and it is all about a Game of Thrones style world. It is a modded Java SMP with a big focus on roleplay and story.
The server has a hand made map based on Westeros. There are places like the North the Riverlands and Dorne and they all feel like they were torn up by wars. You explore and try to claim land for your house.
The cool part is the political system. Power is something you earn. You lead a house and try to keep influence and stability and royal favor. Other players can plot against you and there is a lot of scheming and drama.
They are looking for builders who want to make big castles and cities. They also want lore writers who like to write history and plots and staff to help run events and keep things fair.
The server is whitelist only so they want a small focused community instead of random people. It sounds like a place for players who want deep roleplay and long stories instead of quick games.
If you like being a king a knight or a sneaky planner this server is made for that kind of play.

