I used AJAX extensively on the SpikeCast web site. The homepage uses dynamic AJAX tabs, similar to those on my portfolio: once a tab is clicked upon, the JavaScript requests the content of a separate page and pulls through a list of videos without reloading the current page.
The video previews are displayed within a JavaScript 'slider'. Five videos are shown at a time; when the 'next' or 'previous' arrows are clicked upon, they animate their way off the screen to reveal another five. If JavaScript is not enabled, the videos appear in a block, so no content is lost. (Although the video player requires JavaScript to work properly, I deliberately made this choice in consideration of users browsing with JavaScript disabled, or who may not have the appropriate software installed — they need to know what they're missing before they decide to enable it!)