I allways liked SkyRoads and since I was starting to learn OpenGL, I've started hacking a simple clone of it...
Galactic Path doesn't have fancy features, just as lighting, shadows, neither background image. And also the spaceship is a plain square.
Use the arrows keys to control the spaceship moviment and spaceship to jump.
It uses the SDL library and OpenGL. Although it was only tested in a GNU/Linux system, it should work fine in others unices (FreeBSD, MacOSX...).
You should have a hardware accelerated card (and the respective driver) or else, it will be really a pain to run it at a decent speed. If you use a X11 system, type 'glxinfo' and check if the 'direct-rendering' entry is marked as 'Yes'.