Synchronous multiroom audio player
SonoBus, a real-time network audio streaming collaboration tool
Play music online. With friends. For free.
Quick(Qt) Online Music Player
AndroidAuto headunit emulator
OctopusNet - SAT>IP Server with various possibilities
Juce Based Network Audio Player
Internet-radio server with web-GUI, it broadcasts music from folders
Audacity AudioMonitor (customized version of of Audacity 1.3-13-b).