Have boxes rotate on a page everytime it is refreshed or opened.
Code for example:
<script type="text/javascript">
// List the box IDs you want to select from.
var randomBoxes = [12919885, 12920039, 12920080];
var randomBox = randomBoxes[Math.floor(Math.random()*randomBoxes.length)];
// Construct the API call below.
document.write("<style>#api_box_iid2039_bid" + randomBox + " .headerbox { display: none; } #api_box_iid2039_bid" + randomBox + " .outerbox { background: #FFF; } </style> <div id='api_box_iid2039_bid" + randomBox + "'></div><script type='text/javascript' src='http://api.libguides.com/api_box.php?iid=2039&bid=" + randomBox + "&context=object&format=js&css=0'></script>");
</script>
</script>