Very simple Zerigo backup script. Original from http://www.programblings.com/2012/07/23/do-you-back-up-your-dns-records/

dnsbackup.rb

#!/usr/bin/env ruby
require 'rubygems'
require 'nokogiri'
dir   = File.join( ENV['DNS_BACKUP_DIR'] || '.', 'zerigo' )
user  = ENV['ZERIGO_USER']
key   = ENV['ZERIGO_KEY']
raise "set ZERIGO_USER" unless user
raise "set ZERIGO_KEY" unless key
raise "set DNS_BACKUP_DIR" unless key

`mkdir -p #{dir}`

list = `curl --user #{user}:#{key} http://ns.zerigo.com/api/1.1/zones.xml`
File.open( File.join(dir, '_list.xml'), 'w') {|f| f.write list}

Nokogiri::XML(list).css('zones zone').each do |node|
  id      = node.css('id').text
  domain  = node.css('domain').text
  output  = File.join(dir, "#{domain}.xml")
  puts "#{domain} (#{id}) => #{output}"

  `curl --user #{user}:#{key} -o "#{output}" http://ns.zerigo.com/api/1.1/zones/#{id}/hosts.xml`
end