Linthesia is a fork of the Windows/Mac game called Synthesia. It is a game of playing music using a MIDI keyboard (or your PC keyboard), following a .mid file.
Synthesia up to version 0.6.1a is Open Source. This project uses the latest source from sourceforge.
To compile, you need a basic c++ toolchain, and satisfy all dependences which are on BUILD-DEPENDS file. Then, just:
$ meson --prefix /usr build
$ ninja -C build
$ ninja -C build install #probably with sudo
Visit https://github.com/linthesia/linthesia for more info.
Join the chat at https://gitter.im/linthesia/linthesia