Pragpub is a project mainly written in OBJECTIVE-C and C, it's free.
Contributions to PragPub magazine
This project contains code written for PragPub_ magazine.
iphone-cuke
From iPhone, Meet Cucumber_
jruby-lab
From Part 1_ of "Everyday JRuby"
jruby-degrees
From Part 2_ of "Everyday JRuby"
jruby-mood
From Part 3_ of "Everyday JRuby"
.. PragPub: http://www.pragprog.com/magazines
.. iPhone, Meet Cucumber: http://www.pragprog.com/magazines/2009-08/iphone-meet-cucumber
.. Part 1: http://www.pragprog.com/magazines/2010-12/new-series-everyday-jruby
.. Part 2: http://pragprog.com/magazines/2011-01/everyday-jruby
.. _Part 3: http://pragprog.com/magazines/2011-04/testing-arduino-code