This is a simple Xcode project file with an NSOpenGLView and probably the bare bones of setup required to get a 3D cube rendered somewhat nicely.
I was tired of getting the itch to mess with 3D now and then, but having to re-learn and configure a simple playground app every single time. :) Hopefully you find it somewhat useful as a barebones starting point for an OpenGL project with Mac OSX and Cocoa.