http://roobasoft.com/blog/2008/09/20/force-googles-clientlogin-to-require-a-captcha/

setup_google_captcha.rb

require 'net/https'

def random_word
  alphabet = ('a'..'z').to_a
  (1..12).inject("") { |s,x| s << alphabet[rand(alphabet.size)]}
end

class GoogleAuth
  def self.login(email, password)
    http = Net::HTTP.new('www.google.com', 443)
    http.use_ssl = true
    path = '/accounts/ClientLogin'
    data = \
    "accountType=GOOGLE&Email=#{email}" \
    "&Passwd=#{password}" \
    '&service=writely'

    headers = \
    { 'Content-Type' => 'application/x-www-form-urlencoded'}

    http.post(path, data, headers)
  end
  
  def self.setup_captcha(email)
    resp = nil
    data = nil
    while true do
      resp, data = GoogleAuth.login(email, random_word)
      break if data.include?("Captcha")
    end
    [resp, data]
  end
end