I was going through splendid OpenGLContext tutorials on Mac, and shadow_2.py tutorial gave a little bit of trouble. By fiddling around, I noticed that it needs a color buffer to be bound, just like win32 does.
So in current trunk, change tests/shadow_2.py line 95 (and perhaps the comment below):
if sys.platform == 'win32':
if sys.platform == 'win32' or sys.platform == "darwin":
Bumped into this on OS X 10.7.2 (Lion), 2.3GHz 13" Macbook Pro (early 2011).
As a side note, current release seems to be already two years old <http://pypi.python.org/pypi/OpenGLContext>. This is what installs through easy_install. Perhaps it would be time to update it?:)