SproutCore

Open Source JavaScript Web Framework for Rich Client development.

http://www.sproutcore.com

Nov'2011 - chunk of team bought/hired by FaceBook. But many key SproutCore people recently created a separate company called Tilde which will continue web-focused Sprout development.

We have also created some build tools that will take care of efficiently packaging your HTML, JS, and CSS for delivery over the web that are based on Ruby. However, Ruby is not required for you to use SproutCore except during development.

Adopted by Apple Computer for MobileMe. They hired the developer.

http://www.appleinsider.com/articles/08/06/16/apples_open_secret_sproutcore_is_cocoa_for_the_web.html

Will this make the lack of Flash on the IPhone less painful?

http://www.roughlydrafted.com/2008/06/14/cocoa-for-windows-flash-killer-sproutcore/