There's an example of showing a module once per session in this recipe page: http://www.metamodpro.com/support/recip … er-session

You can easily modify this to only show the modules to non-logged-in users. In fact, you should just be able to use the "Show Quick module(s) to" selector to restrict the access to only people who are not logged in. (despite the label, it affects the PHP rules as well as the Quick Module ID Include).

Does "once per session" cover your needs, or do you really want to show the module, for example, "on every page for the first 5 minutes someone is on the site" ? That's certainly achievable, just takes a little longer to code.

Hope that helps,
Stephen

Ok, here's how to make the modules only appear for the 1st 10 minutes of any user session. So if they come back in a different session, then the modules will re-appear for the 1st 10 minutes.

if ($MM_LOGGED_IN) return; // short-circuit: return nothing if user is logged in
$session =& JFactory::getSession();
$starttime = (int)$session->get('modulestarttime');
$seconds = 10 * 60; // 10 * 60 = 10 minutes
$moduleid = XXX; // replace XXX with the module id of the module to display
if ( $starttime == 0 ) {
  $session->set( 'modulestarttime', time() );
  return $moduleid; // they just entered the site
}
if ($starttime + $seconds > time() ) {
  return $moduleid;
}