anchor.diff:  
   <%= render 'block_location' %>
   
  +<!--
   <div class="block">
     <h2>Itinerary</h2>
   </div>
  
positive.code:   <% else %>
      <p>No one has signed up yet...</p>
    <% end %>
  </div>
negative.code: <div class="block block-alternate">
    <h2>Sponsors</h2>
  </div>
  
  
  <div class="block">
    <h2>Attendees</h2>
  