em_timer.rb

require 'rubygems'
require 'eventmachine'
require 'feedzirra'
require 'restclient'

feeds_url = [ "http://stackoverflow.com/feeds/tag/ruby-on-rails",
  "http://stackoverflow.com/feeds/tag/ruby",
  "http://stackoverflow.com/feeds/tag/git",
  "http://stackoverflow.com/feeds/tag/mongodb",
  "http://stackoverflow.com/feeds/tag/nginx",
  "http://stackoverflow.com/feeds/tag/capistrano",
  "http://stackoverflow.com/feeds/tag/vim"]

EventMachine.run {
  feeds = Feedzirra::Feed.fetch_and_parse(feeds_url).values
  timer = EventMachine::PeriodicTimer.new(5) do
    feeds.map do |feed|
      Feedzirra::Feed.update(feed)
    end

    feeds.each do |feed|
      if feed.updated?
        feed.new_entries.each do |fe|
          puts "new entries : #{fe.inspect}"
          RestClient.post('http://open-notification.com/messages',
                          {'body'=> "News entries on feed #{fe.url} ",
                            'api_key' => 'xxxxx',
                            :message_kinds => {'0' => {'channel' => 'jabber', 'to' => 'cyril.mougel@gmail.com'}}})
        end
      end
    end
  end
}