YoxView is a free Lightbox-type media and image viewer jQuery plugin. It's easy to use and feature-rich. Images, videos, inline content, iframes, Flash contents are supported.
rlightbox is a jQuery UI mediabox that can display many types of content such as images, YouTube and Vimeo videos. It has many unique features like Panorama and Live Re-size. Like other jQuery UI widgets, it is ThemeRoller ready.