Multilink is a quick extension of Prototip2 (which in turn uses Prototype). You will need to download and include both Prototip and Prototype. When you click on a link, you get a tooltip with a list of links (see example below). Just download and include multilink.js and put the following code after your links:
<script type="text/javascript">
new Multilink('ID 1', [{title: "Link 1 Title", url: "Link 1 URL"}, {title: "Link 2 Title", url: "Link 2 URL"}]);
</script>
And so on. Make sure to give your original links ids, since that what is referenced in the first parameter of Multilink().
This is a link and another one.