Dave Lynch owns a guitar workshop in Sacramento, California. One day, the bell on his front door broke off. Since he was in a guitar workshop, he made an appropriate replacement: a guitar mounted above the door.
Over the 9 years that have followed, Lynch has perfected and marketed his design. It's now easy to mount the Guitdoorbell over a door. Opening the door brushes a pick over a guitar, which isn't damaged in the process. In fact, the owner can remove, play, and replace the guitar easily.