Dynamic data is a very cool feature of the ASP.NET 3.5 Extensions that allows you to trivially easy build, customize and maintain a data driven web application... If you have a project that starts with some data in a database and you want to enable, viewing, editing, filtering, sorting of that data in all kinds of interesting ways then you have to check out Oryx..
David has done a very good Screencast that takes everyone's favorite Northwind database and shows how to build a very cool site out of it.
Here is a quote from the forums about this release that I just love:
I installed everything and ran it using Visual Web Developer express. It works. Damn scary to create something that would take a day to create in only 3 minutes
The Dynamic Data Quick Starts can you you going quickly on kicking the tiers.
David has a great post introducing Dynamic Data
Marcin has a great post on adding custom metadata providers in ASP.NET 3.5 Extensions Preview
I'd love to hear what you think!