It looks like the "Flickr Photo Demo" might become the "hello world" of web client frameworks. First the 280 North team released the Cappuccino framework and published their Flickr Photo Demo. Then the broken digits blog released a version written with the help of jQuery.
I've been wanting to improve my Prototype and Scriptaculous skills so I took the broken digits example and replaced the jQuery code with Prototype and Scripty code (yes, I borrowed all heavy lifting on the HTML and CSS work from broken digits). My version can be found here.
If you are interested in arguing the future of these frameworks...bah, I'm going to sleep.