Metronaut - An app to help you play classical music
Concertmaster - Classical music front-end for Spotify
Flat for Education - The best way to teach music to your students
Music-Map - The Music-Map is the Tourist Map of Music, part of Gnod, the Global Network of Discovery.
Scribd Sheet Music - All the sheet music, books and comics you want for $9/month
Poly-graph Hip Hop - See what hip hop's billboard top 10 sounded like