Well... just a few quick ideas about what could be done with group of friends who are right there with you.

First of all it would be cool to be able to easily send music to friends that are nearby. It probably isn't hard even now using bluetooth, but if it were integrated into media player then it might make it even easier.

Another idea is networking nearby devices for your choice of media editing & sharing. For example stream the music you're listening to your friends' devices or share a desktop to show your images so that everyone sees the same image on their own device. There might be some nice applications also if you could simultaneously snap a picture with all the cameras on your nearby friends devices and then get the images easily to your device... It would allow you to get several pictures from the same object at the same time - or see what's happening at different places at exactly the same time.