To randomise content on one of your single design pages, do this in HTML mode:
Put this in your page header, it starts by hiding all the DIVs from your content area.
<style>#home1,#home2,#home3,#home4,#home5,#home6,#home7 { display: none;}</style>
Put this in your page content, this way you can edit all the sections easily... but only 1 actually displays when viewing the site.
<DIV ID=home1>first optional content</DIV>
<DIV ID=home2>second optional content</DIV>
Put this in your page footer or EndCode.html. The EndCode is found under "Custom Design Templates" > "EndCode.html". Change the 6 to however many DIVs you have. This script just selects one DIV to display at random, thus achieving what you want.
<script type="text/javascript">
var numDivs = 6;
document.getElementById('home'+(Math.floor(Math.random()*numDivs)+1)).style.display = 'inline';
</script>