These are my ideas for how to implement helpers using Ruby 2.0 refinements. See http://blog.davidegrayson.com/2013/01/ruby-20-helpers-should-be-refinements.html

idea1.rb

# This fails.  I think the refinements are loaded into the scope
# only when #using is called, and additional refinements that are
# added to the Helpers module later have no effect.

module Helpers
  refine Class do
    def helper(mod)
      klass = self
      Helpers.module_exec do
        puts "#{klass} wants to use #{mod}, self=#{self}"
        refine(klass) { include mod }
      end
    end
  end
end

module MyHelper
  def add(a,b)
    a + b
  end
end

using Helpers

class MyClass
  helper MyHelper

  def join(str1, str2)
    add str1, str2
  end
end

puts MyClass.new.join("a", "b")  # => NoMethodError for 'add'