Parallel - Listen to music with friends over Spotify at the same time
Jukebox - Collaborative music player
Slackbox - Spotify playlist collaboration through Slack
Festify - Festify is a free Spotify-powered app that lets your guests choose which music should be played...
Join My Playlist - Listen to music live together with your friends in Spotify.
TuneMeet - Chat with people who are listening to the same song