Sim Civ MMO

A Sim City / Civ style MMO. Players can trade with each other. Taking from Minecraft, rather than having a strict tech-tree, there is an implied on that certain resources make it easier to get other resources. Really, as I go into more depth, it becomes more and more Dwarf Fortress like (I should probably take some time and play that).

I could pull in a "Fire Upon The Deep" theme and have 'zones' where technologies will not work.

Technologies will go from stone age to futuristic.

Basic buildings are atomic, but more advancing building (like castles) become modular. I could possibly even incorporate "human machines", so a castle may have a lookout tower that communicates with a draw bridge, or several lookout towers that communicate with each other, eventually reaching the draw bridge.

It would be interesting to allow players to 'steal' citizens from each other by bribing them away.