Hi all,
When I was first figuring out how to call my ObjC classes from MacRuby, I greatly benefited from Pieter de Bie's excellent minimal, xcode-free example of this, macruby-bundle-example. I spiffed it up a bit. Here's the github link: http://github.com/diffengr/macruby-bundle-example.
It might be helpful to link to this or its like in future tutorials on this subject.
Cheers,
Clay