gistfile1.rb

class BlankSlate
  instance_methods.each { |m| undef_method m unless m =~ /^__/ }
end

class Delegated < BlankSlate
  attr_reader :delegate
  def initialize(delegate)
    @delegate = delegate
  end
  
  def method_missing(name, *args, &block)
    @delegate.send(name, *args, &block)
  end
end

array = []
delegated = Delegated.new(array)

                           # MRI/YARV/JRuby  # Rubinius

delegated.class            # Array           # Array
delegated.kind_of?(Array)  # true            # true
delegated.object_id        # 80250           # 16

array.class                # Array           # Array
array.kind_of?(Array)      # true            # true
array.object_id            # 80250           # 16

array == delegated         # true            # true
delegated == array         # true            # true

Array === delegated        # false           # true
Delegated === delegated    # true            # false