Scrappy but very simple (and working!) Ruby + Twilio public voicemail system example - live demo at http://voicemail.coder.io/

config.ru

# Very simple, but working, voice message system for Twilio in Ruby
# by Peter Cooper - http://twitter.com/peterc
#
# SEE A LIVE DEMO AT http://voicemail.coder.io/
#
# You can call the Twilio number, leave a message, as well as see the
# messages that are left.
#
# To set up on a server, just have this	as the config.ru (yes, scrappy)
# on a Rack compliant server. Works great with Passenger..
#
# In Twilio, just set the root as the endpoint for your app.
# Access the root in a Web browser to see the voicemails.

require 'rubygems'
require 'sinatra'
require 'twiliolib'
require 'nokogiri'

class BasicVoicemail < Sinatra::Application
  API_VERSION = '2008-08-01'
  ACCOUNT_SID = 'REPLACE WITH YOUR OWN'
  ACCOUNT_TOKEN = 'REPLACE WITH YOUR OWN'

  post '/' do
    @r = Twilio::Response.new
    @r.addSay("Please leave a message. Include your name and press any digit to end. Maximum length is three minutes.", :voice => "woman")
    @r.addRecord(:action => '/phone/recorded', :method => 'POST', :timeout => '4', :transcribe => 'false', :maxLength => 180)
    @r.addSay("You did not leave a message. Stop wasting my time and piss off.")
    @r.respond
  end

  post '/recorded' do
    @r = Twilio::Response.new
    @r.addSay("Thank you. Goodbyte!", :voice => "woman")
    @r.respond
  end

  get '/' do
    account = Twilio::RestAccount.new(ACCOUNT_SID, ACCOUNT_TOKEN)

    resp = account.request("/#{API_VERSION}/Accounts/#{ACCOUNT_SID}/Recordings", 'GET')
    fail unless resp.is_a?(Net::HTTPSuccess)

    @voicemails = []
    Nokogiri::XML(resp.body).css('Recording').each do |recording|
      @voicemails << { :sid => recording.at('Sid').inner_text, :created_at => recording.at('DateCreated').inner_text }
    end

    erb %{<h1>Voicemails received</h1><ul>
      <% @voicemails.each do |voicemail| %>
        <li><a href="https://api.twilio.com/#{API_VERSION}/Accounts/#{ACCOUNT_SID}/Recordings/<%= voicemail[:sid] %>.mp3"><%= voicemail[:created_at] %></li>
      <% end %>
    </ul>}
  end
end

run BasicVoicemail