Aaron Hillegas' book "Cocoa Programming for Mac OS X" has all the examples in Objective-C, I don't write Obj-C, I've tried, I'll probably try some more.
In the meantime, however I've been tooling about with Macruby. I'm going to go through the book (or try, I've never had enough time to get past chapter 4 or 7 or something) and convert the examples to something that works in Macruby.