Apparently, the site was down for a while without my noticing, for which I apologize. My hosting company recently upgraded the Perl version on its servers, which made some of the code in version of Drupal I use obsolete. As a result, the whole site crashed in the most ugly way possible. On top of that, I've been extremely busy recently and hadn't been checked on things in some time (much longer than I should). I normally rely on notifications to let me know when things need attention, but of course since the whole site was down, that wasn't happening either. Everything should be back to normal now. I apologize for the inconvenience, especially to those of you who link to pages here for your classroom use.