hax.rb

    def Session::callback(dbman)  #:nodoc:
      Proc.new{
	dbman[0].close unless dbman.empty?
      }
    end
    def initialize(request, option={})
    #blah blah
      @dbprot = [@dbman]
      ObjectSpace::define_finalizer(self, Session::callback(@dbprot))
    end

leakyleak.rb

class Hax
  def self.callback(obj)
    Proc.new do
      puts obj.inspect if obj
    end
  end
  
  def initialize
    @hax = "asdf"
    ObjectSpace::define_finalizer(self, Hax.callback(@hax))
  end
end

class HaxController
  def initialize
    @hax = Hax.new
    @hax = Hax.new
    @hax = Hax.new
  end
end
loop do
  500_000.times do
    HaxController.new
  end
  puts "run"
  sleep 1
end