Knowthelist - Knowthelist - the awesome party music player Easy to use for all party guests
Jukebox - Collaborative music player
Song Director - Song Director is a program that plays and keeps track of all your music files.
Festify - Festify is a free Spotify-powered app that lets your guests choose which music should be played...
MixTape - Home of MixTape, an OSX application for creating beat matched mixes with simple export to the web or iTunes.
PartyOn - Let everyone DJ together, anywhere