Pimcore is a feature-rich and robust PHP content management system, that is built with Zend Framework, for creating and managing digital content + assets.
The interface is powered with ExtJS and almost all editing is done via drag 'n' drops.
It is possible to work on multiple documents at the same time with the help of the multi-tabbed usage.
Pimcore is also a product information management framework (PIM) which means true multi-channel publishing and integration into ecommerce systems like Magento and OXID eSales.
The application is powerful on controlling digital assets as well. It can be integrated to the desktop using WebDAV or to the 3rd party systems via web services.
For images, it can analyze them automatically (EXIF data), create thumbnails and enable you to edit them (rotate, crop, etc.).
If the assets are documents, it offers web-previews using a Scribd account. And a similar preview works for videos using Youtube.
Pimcore has many other advanced features like versioning, built-in caching, permission-based user management, multilingual interface and much more.
Requirements: PHP 5.3+, MySQL 5+, *nix system
LiveUI is a powerful, flexible & open source rich internet application framework for .NET.
It has a modular system which allows sharing .ascx user controls & resources between ASP.NET web applications.
LiveUI has an Extjs.Controls module which includes ASP.NET wrappers for all ExtJS components making usage of them so easy inside ASP.NET pages.
Also, there is a built-in solution for URL parsing & generation which means creating user friendly URLs is not a problem with the framework.
Requirements: .NET 3.5 sp1+
AeroSQL is an open source web application, for managing MySQL databases.
It can control databases from different servers in a single, desktop-like interface where records can be easily browsed or edited within a grid.
The application displays every query executed & can run a batch of sql queries to save you time.
It is possible to select the columns to be displayed while editing a table which will help reaching the data in an organized way.
AeroSQL is built with PHP & uses ExtJS to provide the desktop-like functionality.
Requirements: PHP & ExtJS