//index.html.erb
XXXX
<%= stylesheet_link_tag 'scaffold' %>
<%= javascript_include_tag :defaults %>
<%= yield(:head) %>
<%= yield %>
//_curvy.html.erb
<% content_for :head do %>
<%= javascript_include_tag 'rounded_corners.inc.js' %>
<% end %>
<%= yield %>
//Calling file (new.html.erb)
<% render(:layout => 'layouts/curvy',
:locals => {:id => "login_form",
:tl => 20,
:tr => 20,
:bl => 20,
:br => 20
}) do %>
conteudo
<% end %>