[Lynne]

I got it working by doing exactly what was done on that minimal example page.

I added this at the end of the headinclude template (you said headinclude.css, that is not correct):

<style type="text/css">
@import "clientscript/jquery.countdown.css";

#defaultCountdown { width: 240px; height: 45px; }
</style>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script>
<script type="text/javascript" src="clientscript/jquery.countdown.js"></script>
<script type="text/javascript">
$(function () {
    var austDay = new Date();
    austDay = new Date(austDay.getFullYear() + 1, 1 - 1, 26);
    $('#defaultCountdown').countdown({until: austDay});
    $('#year').text(austDay.getFullYear());
});
</script>

And then I created an HTML block with this content:

<div id="defaultCountdown"></div>

So, get the very minimal working first (like above) and then go making changes to change buttons and dates and such.