Programming a custom redirect in a Drupal Site
You could do something along the lines of this: 

function MYMODULE_menu() {

  $items['MYMODULE/whattodo'] = array(
    'title' =&gt; 'Where should I go now, George',
    'page callback' =&gt; 'MYMODULE_whattodo',
    'access callback' =&gt; TRUE, 
    'type' =&gt; MENU_CALLBACK,
  );

  return $items;
}

function MYMODULE_whattodo() {

  $foo= // code to get the current time of day in whatever form you want that matches the switch cases below

  switch($foo) {
     case // morning:
        drupal_goto(// page for the morning);
        break;
     case // afternoon:
        drupal_goto(// page for the afternoon);
        break;
     case // evening:
        drupal_goto(// page for the evening);
        break;
  }
}


which means when a user went to www.mysite.com/MYMODULE/whattodo, they would be redirected to whatever page you set up via drupal_goto()