UI-Patterns are not the first to create a UI design library. A popular design library is the Yahoo! Design Pattern Library. While very useful, it is far from complete. The purpose of this site is over time to fill some of the gaps – especially by providing code examples as to how how the different patterns can be implemented.
Some of the patterns introduced are really interesting, but the way they are presented is a few steps behind Yahoo's. It's still great work, and I can't imagine how difficult is to formalize those patterns, but having a video showing the pattern in action is an advantage over plain screenshots.
Another site on user interface patterns I found is Welie, which covers a good list of common practices in interaction design.
So for those interested in getting to know more about design patterns for the user experience, here is an interesting presentation in Yahoo! User Interface Theater, called "Designing the Rich Web Experience: Principles and Patterns for Rich Interaction Design on the Web". Enjoy!
Bill Scott served as a Yahoo Ajax Evangelist and engineering manager from 2005-7. In this talk, given at nearly a dozen conferences around the world, Bill taxonomizes the rich interaction patterns that characterize the evolving web — a must-see for web designers and frontend engineers