Not quite sure, actually.
Most of my builds are tied up with friends, so, I work on it when they want to work on it.
At the moment, it's probably a Medieval town I'm working on with a few friends. I've so far built a large church and was half-way through building some form of Archery Shop.
I'd then build houses and other essentials for the town afterwards.
I'm sort of in the discussion with a friend right this second though, to do a sort of "Survival/Challenge/Competition" build.
Just going over the concept now.