PongMe gives you all information you need around you in a passive way.
When one wants to visit a city, he can first check on the web to find what can be insteresting. But with this application he can just wander around: the app will notify the user whenever there is something that fit his/her interest (thanks to Open Data sources, Google Maps directions, Wikipedia,...).
It works with 3G cell positionning, not to let the GPS empty the battery too quickly (only with Paris data).
Winner of the Paris Android Dev Camp 2012 App Contest (Smartwatch)