This was filmed in San Diego, and if you're wondering how he did it:

I wrote the music and recorded it first. The frames were photographed with a Canon Rebel using 20-30 second exposure time. I used a small green LED keychain light to draw each frame. Once all the positions were photographed they were strung together and synchronized to the music in After Effects.

Light-Paint Piano Player from Ryan Cashman on Vimeo.

[Ryan Cashman via Today and Tomorrow]