Hello,
That page has javascript errors on it, which are breaking the menu. You will need to disable all third party scripts on the page to determine which is causing the problem. I can see one with an issue right away:
<script type="text/javascript" src="
http://mercury-sail.com/plugins/content/photogallery/js/jquery.lightbox-0.5.min.js"></script>
Jquery should never be called by itself, it should always be called from the core of Joomla, and this extension is introducing it's own copy. That creates conflicts with the core Joomla jquery call.