Heartbeat - Listen to music with your friends together, on Spotify
humit - A social networking app for music sharing and discovery.
Partyhero - Pass your friends the aux!
Vertigo - Vertigo is a web and Android application that allow you to listen to music with friends in real-time.
Twinjack - Stream Spotify music with anyone with just a link
CueBot - A better way to request for songs at a party 🎉