This portion of the page could contain any HMTL-based information including links to additional pages while keeping the HyperStudio timer running in the upper portion of the page in its own frame.  It could not, however, have a second stack running as the HyperStudio Plugin only supports one stack at a time.  For example, this link shows a Shockwave movie (that should be timed!), while this link takes you to an interactive math puzzle.