Oomerang: geolocation-based lost & found06 Dec 2013
Oomerang is an app that helps return lost items to their owners based on an approximate lost or found location.
See items people have posted in a particular area, or simply drop a pin on the map and enter a few details to add an item yourself. You can also get in touch with anyone who's posted something you recognize.
It's a Rails app that uses the Google Maps and Google Places APIs, with lots of AJAX on the front end and a responsive Bootstrap UI. Connecting users by email happens via Action Mailer.