Update: Recent changes in Facebook's Graph API have made it impossible to do this now.
I came across a Facebook application that plots one's FB friends' locations as a heatmap on Google Maps. Being the inquisitive geek that I am, I decided to make one myself. I went around learning about the Graph API of Facebook. I soon realised that there was a Python module named Facepy to implement this in Python. Soon, the setup was ready and I ran the code to fetch the location of my friends. I hit my first roadblock. Facebook's privacy settings didn't allow me to fetch the locations. I started to look for some loophole in this. I did a quick Google search and realised that the latest Graph API version(2.0) doesn't allow to do what I was planning to do.
I was almost on the verge on giving up when this thought came to me. If the API doesn't allow this, how on earth did the app I had come across earlier work?? It was already late in the night(the next day morning actually) and I was still thinking about this with Snickers, tea and various other junk food. This is when I realised something very important. Version 2.0 doesn't allow to fetch locations. So, what about the previous ones? I had a breakthrough. I quickly went to the Graph Explorer tool on Facebook to check the access token generation tool. There was a small option near that text field where I could choose the API version. Voila! After a few test runs analysing the format in which the response was, I quickly created a heatmap with Google Maps API.