gistfile1.rb

require 'rubygems'
require 'dnssd'

@hosts = Array.new
DNSSD.browse! '_mongodb._tcp' do |service|
  DNSSD.resolve! service do |r|
    @hosts << {:host => r.target, :port => r.port}
    break unless r.flags.more_coming?
  end
  break unless service.flags.more_coming?
end
@hosts.uniq!

puts @hosts.inspect