http://www.musicgames.co/game/1562/notessimo/

is fun and

and this page is not bad:

http://www.musicgames.co/games-by-category/educational-music-games/

Maybe these will be useful:

Chow, J., Feng, H., Amor, R., & Wünsche, B. C. (2013, January). Music education using augmented reality with a head mounted display. In Proceedings of the Fourteenth Australasian User Interface Conference-Volume 139 (pp. 73-79). Australian Computer Society, Inc..

Birch, H. (2013). Motivational Effects of Gamification of Piano Instruction and Practice (Doctoral dissertation, University of Toronto).

Hi,

Jeffrey Agrell has many books about imrpovisation games: http://jeffreyagrell.com/books/

I think this is not exactly what you are looking for.

or this one

http://www.iupress.indiana.edu/product_info.php?products_id=88774

I tried this at the ITS 2014. Considering I have no clue about music, i think I did quite well. Perhaps it helps you:

https://www.researchgate.net/publication/269873077_P.I.A.N.O._Faster_Piano_Learning_with_Interactive_Projection

Conference Paper P.I.A.N.O.: Faster Piano Learning with Interactive Projection

Thank you very much for your answers. I found many different aspects in these sources helping my research. And I just stumbled upon this nice chamber-music-app: http://digital.juilliard.edu/string-quartet