While working at Oakwood I did a few projects involving a guessing game for song releases. The basic concept is that you would listen to the instrumental version of the song and guess the lyric. As people guess correctly, parts of the music starts to get vocals until the whole song is released.
My main role in those project was to provide both a backend for the guessing game, queueing of players and a secure server infrastructure to create the versions of the song with the correct instrumental and vocal sections. I also did a few versions of the front-end but they didn't get published.
One example of this concept is Veronica Maggio's release of the song Ayahuasca