This named route handles urls such as: http://www.mysite.com/tags/wicked
which would route to controller => 'tags', :tag => 'wicked'
while creating named routes tag_path and tag_url.
The singular naming method keeps inline with REST conventions in Rails.

map.tag 'tags/:tag', :controller => 'tags', :action => 'show', :conditions => {:method => :get}