we're working on a live party visualizer using raspberry pi's deployed as iBeacons. We're writing an iPhone app that detects the user's location (based on the ibeacon) and updates a server. We're writing a d3 visualization that renders the user's location graphically in real-time based on the aggregated server data.

doesn't exactly cure cancer, but it's pretty cool. Obvious uses for retail, etc (but all that stuff is lame.. it's more fun to use at a party)

..and that's what we're working on.