gistfile1.builder

module Awesomeness
  def hello
    puts "hello"
  end
  def self.included(klass)
    klass.class_eval { include Awesomeness::ClassMethods }
  end
  module ClassMethods
    def hello
      puts "YAY"
    end
  end
end

class Person
  include Awesomeness
end

Person.hello => "YAY"
Person.new.hello => "hello"