With 250,000 NTD invested, 6 man power allocated, and 9 month time elapsed, we present BLLive. The seemingly dumb, senseless BL Hall at National Taiwan University is transformed to an intelligent office building by a 30+ node sensor network. Two everyday services, Elevator Report and Smart Office, are implemented to better utilize the resources of the building and of the building residents. Our experience allows us to re-examine technical issues such as manufacturing cost, form factor, deployment, data communication, and energy efficiency. Many of the lessons we learn are not only surprising but also inspiring, which in turn leads us to think that more deployment experience and experience sharing are critical to the advances and commercialization of sensor networks.