Without a doubt the most unusual instrument I've seen played by a street performer in Santa Cruz was this upright piano. It was pretty beat up but he had in in perfect tune and it sounded great. He and his friend(the other guy in the photo) would push it from one spot to another when they needed to move to avoid violating the street performance time limit set by the municipal code.
For more on the Steemit photo Challenge see this post:
https://steemit.com/steemitphotochallenge/@jamtaylor/steemit-photo-challenge-winners-action-68