card.rb

require 'drb/drb'

ro = DRbObject.new_with_uri(ARGV.shift)

name = 'your_nick'
url = 'http://your_page'
desc = 'your comment'

p ro.exchange(name, url, desc)

card_holder.rb

require 'rinda/tuplespace'

module Rinda
  class Njet
    def initialize(value)
      @value = value
    end
    
    def ===(other)
      @value != other
    end
  end
end

class CardHolder
  def initialize
    @ts = Rinda::TupleSpace.new
    @ts.write(['m_seki', 'http://d.hatena.ne.jp/m_seki', 'Hello, Again'])
  end

  def exchange(name, url, desc)
    @ts.write([name, url, desc])
    @ts.take([Rinda::Njet.new(name), nil, nil])
  end
end

DRb.start_service('druby://:56789', CardHolder.new)
puts DRb.uri
DRb.thread.join