This client wishes to organize ongoing conferences, in Spring and Autumn of each year.  Each conference has its own url prefix, such as 'spring2013' and 'fall2013'.  This was achieved by using Drupal 7's hook_inbound_alter and hook_outbound_alter meaning that these urls did not need to be set in code.  Each conference is controlled from a single content type making it easy to set up a conference.  When browsing a conference, session variables hold information about the current conference so that all information displayed relates only to that conference.  The result is a dynamic and lightweight means of managing multiple ongoing conferences.