I have been to couple of hackathons. My second favorite is WikiNomad: https://play.google.com/store/apps/details?id=com.wikinomad https://play.google.com/store

I have been to couple of hackathons. My second favorite is WikiNomad: https://play.google.com/store/apps/details?id=com.wikinomad https://play.google.com/store/apps/details?id=com.wikinomad , https://www.wikinomad.com https://www.wikinomad.com I improved on this after the hackathon too. My personal favorite was predicting depression before it occurs in a person using just his cellphone. We worked on Stanford thesis that was able to predict depression based on the number of wifi points a user connected to variances to the wifi points. We increased the data points to GPS, wake times, bluetooth connections, text sentiment analysis and amount of facebook + instagram apps usage and using neural networks trained to classify a user as depressed with a probability value.