iframeLightBox
Do you have something you want users to see without leaving the page? Don't want to do a lot of fancy AJAXing or annoy your users with popup windows? Maybe you should try iframeLightBox.
Call it like so:
<p>Please read the <a href="tos.html" class="pop">terms of service</a>.</p>
<script type="text/javascript">
iframeLightBox('pop');
</script>