In Edmonton, Canada, a piano has been placed in their Underground train system so that anyone can play it. It’s the brainchild of David Rauch (who you can see in this video) and his OpenPianoYEG project. The special thing about this piano is that it’s connected to the internet. The piano has a Raspberry Pi embedded into it which records the public playing music, converts it to MP3 and then uploads it, tweeting to the @OpenPianoYEG twitter account. Read more about it in this Edmonton Journal article.