nav_highlight.html.erb

<%
nav_classes = { "articles" => nil, "episodes" => nil }
nav_classes[controller_name.underscore] = "current"
%>
<%= link_to "", articles_path, :id => "articles", :class => nav_classes["articles"] %>
<%= link_to "", episodes_path, :id => "episodes", :class => nav_classes["episodes"] %>