This is a little jukebox you can run on your raspberry pi that accepts youtube video slugs, downloads the music, and plays it. You might wonder why you'd want something like this. I don't know why YOU would - but I used it to prank my office coworker by connecting my pi3 to their bluetooth speakers and handing control of this little jukebox off to everyone else in the office.
Clone the repo, then install the dependencies:
sudo apt install ffmpeg python3-pip
pip3 install youtube-dl
python3 jukebox.py
You can do two things - you can retrieve the current play queue, or you can queue up a new song.
Get the current play queue:
wget localhost:8888
Queue up a new song:
wget localhost:8888/queue/<id>
where <id> is the unique identifier of the youtube video you want to pull the audio from.
E.g., for the url https://www.youtube.com/watch?v=JJ9IX4zgyLs, the id is JJ9IX4zgyLs.
Obviously, unless your firewall is blocking it, you should be able to control your little jukebox from another PC by replacing localhost with your pi's IP (or hostname, if you have local DNS).