roberto

<% flash.each do |type, message| %>
  <div class="alert <%= bootstrap_class_for(type) %> fade in">
    <button class="close" data-dismiss="alert">×</button>
    <%= message %>
  </div>
<% end %>

potomak

<% [:notice, :error, :alert].each do |level| %>
  <% unless flash[level].blank? %>
    <div class="alert-message <%= flash_class(level) %>">
      <a class="close" href="#">×</a>
      <%= content_tag :p, flash[level] %>
    </div>
  <% end %>
<% end %>