Routing Module to mixin

I have a need to get routes into my AR models, but I can not find the module that provides them to ActionController. For example, I would like to provide an event feed from two different locations, so want to do something like this;

xml.instruct! :xml, :version => '1.0' xml rss stuff @events.each do |event|   event.to_rss(xml) end

Event.rb def to_rss(xml)   xml.item do     xml.link(event_url(self))     xml.guid(event_url(self))   end end

but AR (rightly) doesn't know how to do event_url() Where does it come from?

Thanks, --Dean