Developing Games With Ruby (2014)
Getting The Sample Code
You can find sample code at GitHub: https://github.com/spajus/ruby-gamedev-book-examples.
Clone it to a convenient location:
$ cd ~/gamedev
$ git clone git@github.com:spajus/ruby-gamedev-book-examples.git
The source code of final product can be found at https://github.com/spajus/tank_island