This was a submission to the 3tap Hackathon by myself and gon - Code and full description are here:
https://github.com/danielsoneg/spiky-world
It's inspired by Richard Florida's "Spiky World" article from The Atlantic. We're pulling in "For Sale" posts from 10 different categories and comparing them across 10 different cities to show which cities "spike" in which categories compared to the rest of the country.
Note this was done in a couple hours - it's Very rough and only runs in browsers which support WebGL.