I grabbed the port of ruby-opengl for OSX from
http://www.lazyatom.com/software/opengl-0.32f.tar.gz and installed it.
 When I try to run any program (or even require 'opengl', I get the
following error, which kills ruby:

objc: failed objc_getClass(NSObject) for GLUTApplication->isa->isa
objc: please link appropriate classes in your program

Trace/BPT trap

I don't know much about OSX programming, so I have no idea what this
means.  When the library links, it does link against the OpenGL and
GLUT frameworks, so I would think it would know where to find the glut
and OpenGL stuff, but maybe it doesn't.  Any help would be much
appreciated.