gistfile1.txt

ruby-1.8.7-p248 > module Foo
ruby-1.8.7-p248 ?>  def self.included(base)
ruby-1.8.7-p248 ?>    def base.do_foo
ruby-1.8.7-p248 ?>      Foo.send :define_method, :write do
ruby-1.8.7-p248 >           puts "1"
ruby-1.8.7-p248 ?>        end
ruby-1.8.7-p248 ?>      end
ruby-1.8.7-p248 ?>    end
ruby-1.8.7-p248 ?>  end
 => nil 
ruby-1.8.7-p248 > module Bar
ruby-1.8.7-p248 ?>  def write
ruby-1.8.7-p248 ?>    puts "2"
ruby-1.8.7-p248 ?>    end
ruby-1.8.7-p248 ?>  end
 => nil 
ruby-1.8.7-p248 > class Thing
ruby-1.8.7-p248 ?>  include Foo
ruby-1.8.7-p248 ?>  do_foo
ruby-1.8.7-p248 ?>  include Bar
ruby-1.8.7-p248 ?>  end
 => Thing 
ruby-1.8.7-p248 > Thing.new.write
2