Simple Presenter pattern in ~30 lines of code.

presenter.rb

require 'delegate'

class Presenter < SimpleDelegator
  def self.model_name
    @_model_name ||= ActiveModel::Name.new(self.name.gsub('Presenter', '').constantize)
  end

  def self.for(objects)
    objects.collect { |item| (item.class.name + "Presenter").constantize.new(item) }
  end

  attr_reader :original
  def initialize(original) ; @original = original ; end
  def __getobj__ ; @original ; end
  def to_model ; self ; end

  # this doesn't have to be Rails-specific, should be usable w/ Sinatra w/ a few tweaks
  module ViewHelpers
    def render_presenter(object, *args)
      render Presenter.for(object), *args
    end
  end

  ActionView::Base.send(:include, Presenter::ViewHelpers)
end