I've included this here partially because I'm a big fan of the show, but also because it's a great site. Over the past few years, I've had the pleasure of working on several projects with our local PBS affiliate, WGBH Boston. One of the biggest undertakings was this site, a full redesign and site framework for American Experience. It prioritizes new episodes, allowing space for supplementary content, and brings years of archives together under one roof.
Though it looks straightforward, the site is really quite deep. Nearly 30 discrete templates are used to handle videos, photo galleries, articles, a blog, and PBS's proprietary commenting system. I worked as half of a two-man dev team, building the XHTML templates to the specifications of the from-scratch CMS our team was creating.
The site is still live and has been well-maintained by WGBH.