Relative URLs can be set a couple of different ways in OSU Drupal, depending on what Drupal element you are using at a given time.
To set a relative URL in the TinyMCE text editor, do the following:
The Page Visibility Settings in any block configuration panel allows a Drupal user the ability to show or hide blocks based on a single URL path or URL pattern. This should always be set relatively. The format is as follows:
For node references: node/#
For aliases: alias
Ex: if there were a node in the CWS Training site at http://oregonstate.edu/cws/training/learn-drupal, the learn-drupal part would be the only thing you would put in.