You might be interested in what I'm setting to out build. I'm working on Archapolis, a city builder with real time traffic simulation and interior views of peoples homes (which you can customize/build yourself if you want). Very early stages of development still.

As for steroids, here's a tech demo of what I've been working on: https://www.youtube.com/watch?v=7q0l87hwmkI

I created a path finding algorithm that can simultaneously path 300,000 units to random destinations at a comfortable frame rate. Units can choose from any of the shortest paths between two points (there are many in a grid), and from those paths, can also choose the path that matches any preferences they have.