GNU Solfege is *free* ear training software written in Python 3.4 using the Gtk+ 3 toolkit. The program is designed to be easily extended with lesson files (data files), so the user can create new exercises.
SDL Sopwith is a port of the classic 8086 biplane shoot-em-up game to modern computers.
Atanks is a multi-platform Scorched Earth clone similar to the Worms series of games. Annihilate the other tanks to earn money, then spend it on bigger and better shields and weapons to wipe out the opposition.