require 'action_view'
require 'action_controller/mime' # for Rails 2

render :file=>'foo.html.erb', :locals=>{:user=>User.first}
render :file=>'lib/data_feed.xml.builder', :type=>:rxml, :locals=>{:user=>User.first)

def render(options)
  klass = Class.new(ActionView::Base)
  klass.class_eval{ def url_for(x);x;end } # to be able to use link_to
  klass.new.render(options)
end