[kh99]

You could make a plugin using hook cron_script_cleanup_daily and code like this:

PHP Code:

if (date("N") == '1') // 1 = Monday, 7=Sunday
{
   $vbulletin->db->query_write("UPDATE rbs_banners SET m_expired=0");
} 


It's not perfect. For one thing if, for example, you set it up to run on Monday and for some reason the cleanup script doesn't run (like your forum is down or something), it wouldn't run until the next week. BUt it might be good enough for your purposes.