gistfile1.rb

 class Factory
    class << self
      def new_thing name
        klass = Class.new(self) do
          attr_accessor :name
          define_method :initialize do
             @name = name
          end
        end
        const_name = name.camelize.intern
        old_klass = remove_const const_name if const_defined? const_name
        old_klass = nil
        self.const_set const_name, klass
        klass
      end
    end
 end

Factory.new_thing "bob"
Factory.subclasses
#[Factory::Bob]
Factory.new_thing "bob"
Factory.subclasses
#[Factory::Bob, Factory::Bob]

# Shouldn't there still only be one Factory::Bob