Freeglut is really simple and seems to be the best library to get started and jump into OpenGL. They also have one of the better beginner tutorials for being able to get started: https://en.wikibooks.org/wiki/OpenGL_Programming. The problem is that Freeglut doesn't support much beyond a window and basic input. So it won't take you much further than quick debug applications.
Linux Geeks doing what Linux Geeks do..