During undergrad, I worked on a few side projects, with most of them using some sort of social-networking API. It was great learning some new skills and at the same time it was rewarding to tap into the vast networks of established sites such as Facebook and Twitter. Cue to postgrad and I had to complete a research component as part of my course requirements. With a nudge from my supervisor I asked the question: "Is it viable to have a generic social networking API? Will it be useful?"
There are already millions of apps available that have great content, and there'll be many more to come. GROUPcentric provides a product that aims to add a new and exciting layer in social sharing functionality that allows content to be shared, not only via the large scale Facebook and Twitter options or email and SMS, but an in-application sharing service that makes it possible for users to privately share content with groups of friends that can be accessed on any app. The GROUPcentric API and SDK allow developers to integrate this functionality with other applications.
For those who get their kicks out of a good old physical board game, BoardGameGeek is a fun application that may be of interest. It's an online board gaming resource and community that is constantly updated in real-time by it's growing list of users. Users from across the world can participate in reviews, ratings and live discussion forums, add images, find play-aids, access session reports and more. BoardGameGeek also provides the BoardGameGeek API which means this functionality can be easily accessed and integrated with other applications.