RssFeed is an open-source custom ASP.NET server control I created to display items from a particular RSS feed. RssFeed works with both RSS 1.0 (RDF) and RSS 2.0...
A common request from the RssFeed user-base has been to make it so that RssFeed could dynamically expand/collapse the descriptions for a blog entry. I first added template support to RssFeed back in version 1.2, thinking that would be sufficient. However, I forgot to give the RssFeedItem class an ItemIndex property, which I think is a vital piece to getting the desired functionality.
In any event, I added this property, updated the code base, and created a live demo illustrating the expandable/collapsable descriptions. (There are also additional live demos of RssFeed you can check out...)
Enjoy!