http://www.fragradio.co.uk/FragRadio is a plugin for servers where it hooks you up to a channel and allows you to listen to music while playing. You can vote on the song, ask for a shoutout, and also get the name of the song currrently being played if you missed it the first time it was said.
I think it would be cool if this was ported into Blockland, we could build, dm, mess around and listen to music.
(It would be nice if it was client-sided, but I doubt that could happen.)