In my current world I took a small, little village and turned it into a large-scale city. It has a lot of buildings and villagers, I love it!
I love modpacks like feed the beast in terms of large-scale projects. I tend to build functional factories, my favorite being a fully automated pumpkin pie factory. It was awesome getting the timing right on everything and automatically harvesting and crafting pies by the stacks.
That's a pretty awesome farm, I have to try building one in my own world as well since I'm lacking pumpkin. I wanted to try out FTB for a while now, what can you do on it except for factories and all the new blocks and weapons?