A business acquaintance recently ran a contest together with Spencer & Broderick, a local promotional video producer, that involved finding beacons, kind of like indoors geocaching. The post also goes through how to use beacons in Titanium.
Indoor treasure hunt using your phone
Actually, geocaching is an interesting non-pro application of beacons. Also consider e.g. orienteering, where you just have to be close to a station to become cleared, and of course the system behind it could collect data on each contestant and show status in real time.