EarMaster - Professional software for ear training and practical music theory on Windows and Mac.
Dancemusic WTF-300 - Quiz game for learning electronic dance music styles
GNU Solfege - GNU Solfege is free music education software.
Icon Pop Quiz - Guess the song
LenMus - LenMus is a free program for learning music.
Musiio Tag - Tag songs quickly using Artificial Intelligence