No live demo, unfortunately. I think archive.org has plenty of public-domain music in ogg format. Want to put something together and I'll link to it in the README? This would be quite nice indeed to have.
On the plus side though, it's super easy to try it out locally using the built-in server:
Give backend/app.cfg the path of the music on your computer. Then run backend/local_server.py. Browse to localhost:5000 in your web browser, and you're set.