A module to fetch an URL in a periodic manner, the period can be selected by module options, also you can store the result complete (For example to get the image of the day for your site, every day, without changing/editing the content item..) or you can store a log with a selectable ammount of bytes to log (so the log size keeps controlled) or just ignore the resulting data (when you don't care what's returned, like in a keep alive situation...).

Read more at: http://extensions.joomla.org/component/option,com_mtree/task,viewlink/link_id,4908/Itemid,35/