Find your data doppelganger
The Human Face of Big Data is a global social media project "that focuses on humanity's new ability to collect, analyze, triangulate, and visualize massive amounts of data in real time". They have an app that you can download and track loads of information about your day and then you can find someone who has the same data profile as you - your data doppleganger. This might be the person with the same phone habits, similar commute and internet habits.
Slightly creepy but strangely fascinating.