I think there should be like /Music which gives you too a link to like a radio type thing were it keeps plays songs over and over all night because then people can be listening to the same stuff over and over! Or /server music which is a plugin that has songs made into note block form!
Play some Pandora on the background when you play Minecraft I don't think this is possible unless you just want note block songs We have those music boxes that play those disks.
