Heartbeat - Listen to music with your friends together, on Spotify
Liyo - Stream your favorite music live with friends 🎶
TuneMeet - Chat with people who are listening to the same song
haminet.fm - Listen to music with your friends while working
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.