# Evaluate the block with the given arguments within the context of
    # this object, so self is set to the method receiver.
    #
    # From Mauricio's http://eigenclass.org/hiki/bounded+space+instance_exec
    def instance_exec(*args, &block)
      puts 'here'
      begin
        old_critical, Thread.critical = Thread.critical, true
        n = 0
        n += 1 while respond_to?(method_name = "__instance_exec#{n}")
        InstanceExecMethods.module_eval { define_method(method_name, &block) }
      ensure
        Thread.critical = old_critical
      end

      begin
        send(method_name, *args)
      ensure
        InstanceExecMethods.module_eval { remove_method(method_name) } rescue nil
      end
    end