asciinema.org/app/views/asciicasts/_asciicast.html.erb

<div class="asciicast">
  <div class="wrapper">
    <div class="player"></div>
    <div class="clear"></div>
  </div>

  <% unless (defined? skip_description) && skip_description %>
    <div class="description">
      <% markdown = Redcarpet::Markdown.new(Redcarpet::Render::HTML) %>
      <%= markdown.render(asciicast.description.to_s).html_safe %>
    </div>
  <% end %>
</div>

<%= player_script(asciicast, :auto_play => local_assigns[:auto_play]) %>