A script to use the Netflix paginated "What You've Rated" to pull what you have rated in Netflix. This call is not exposed in the Netflix API so it's hard to get any other way. This is quick and dirty so not the best Ruby constructs.

ratings.rb

#!/usr/bin/env ruby
require 'iconv'
require 'nokogiri'

# This is a simple script to spider your Netflix paginated "What You've Rated" list.
# It requires an OS X based system with Ruby 1.9+, Safari, and AppleScript
#
# I could not find a way to back up my ratings (for all titles, not just my rental activity)
# without registering for a Netflix API key or handing my Netflix credentials over to someone
# who had an API key, so I decided to take a brute force approach and just parse the HTML for
# every page of my ratings history on Netflix's site.
#
# INSTRUCTIONS:
#  1) Launch Safari, visit Netflix.com, log in if necessary, and visit your "What You've Rated"
#     page. If the URL for page 1 differs from that of the STARTING_URL variable below, then 
#     update the variable's value. Leave the browser open on that page.
#     for this script to write the ratings to.
#  2) Set the PAGE_LOAD_GRACE variable equal to the number of seconds that you would like to
#     give Safari to fully render each individual ratings history page before grabbing the
#     HTML source for the page.
#  3) Execute this script ($> ruby <scriptname>) and be careful not to interfere with Safari
#     while it visits each page in your ratings history.

# Config
STARTING_URL    = 'http://movies.netflix.com/MoviesYouveSeen'
PAGE_LOAD_GRACE = 4 # seconds of grace to allow for Safari to finish rendering a single page of ratings

# Character encoding converter instance used to force all HTML output into UTF-8 format
ICONV           = Iconv.new('UTF-8//IGNORE', 'UTF-8')

# For the given page's worth of Netflix ratings, glean out the title, Netflix URL,
# genre, and rating for each entry.
def glean_movie_info(html, ratings_array=[])
  next_url = nil
  page = Nokogiri::HTML(html)
  page.xpath('//table//tbody//tr').each do |row|
   title=row.xpath('.//td[@class="cell-title"]').text.strip
   genre=row.xpath('.//td[@class="cell-genre"]').text.strip
   rating= row.xpath('.//td[@class="cell-starbar"]//span[contains(@class,"stbrMaskFg")]').text.strip.split(":")[1].strip
   puts "#{title}|#{genre}|#{rating}"
  end
  next_url=page.xpath('//a[contains(@class, "next")]').first
  next_url.nil? ? "" : next_url["href"]
end

# Obtain the HTML source for the given URL
def fetch_html(url)
  applescript = <<-EOF
    tell application "Safari"
      activate
      set url of document 1 to "#{url}"
      delay #{PAGE_LOAD_GRACE}
      set htmlSource to source of document 1
      set the clipboard to htmlSource as text
    end tell
  EOF
  ICONV.iconv(`osascript -e '#{applescript}' && pbpaste` + ' ')[0..-2]
end

# Starting with the first page of ratings, keep gleaning ratings info
# and moving on to the next page until the last page (which will not
# have a "next" link at the bottom). Keep adding each page's worth of
# info to the ratings array, which contains a hash of info for each movie.
url_to_fetch = STARTING_URL
ratings = []
until url_to_fetch == ""
  url_to_fetch = glean_movie_info(fetch_html(url_to_fetch), ratings)
end