Joomla article layout random order

Looking for a programmer familiar with joomla cms. I have a pretty simple problem. In my article layout currently I am using the blog layout. For example view this link [login to view URL] I need the order of the articls to show in random. Currently I am only able to sort by date and a-z and such. My request is for someone to help me figure out how to make this work where my articles will show in random order every time the page is refreshed.