AJAX

"JavaScript can do great things for rich interactions, but depending on AJAX makes everything nearly as slow (and as performance-expensive) as a full page reload." JQuery updating the page right away from the data you already have on hand (no http post request) and other best practices.

Views Slideshow: Dynamic Display Block module is a views_slideshow plugin mainly used to showcase featured content at a prominent place on the frontpage of the site in an attractive way. A featured content slideshow can contain e.g.: New articles, Most popular content, New products, Portfolios, etc.

Detailed example of adding AJAX to Drupal node form, in this case to add more fields (non-CCK).