Web OS to host web based applications. An API allows to create online applications. Uses web 2.0 techniques. Integrate existing web apps. Featuring: GUI, icons, tasks, users. Office apps: oulook, CRM, browser, browser, post-it, mail.
pVigil is an Objected Oriented Bug/Issue manager API (LGPL) written in PHP and several "example" user interfaces (GPL) such as e-mail, web, windows (VB) and Soap/XML-RPC. It uses the file system for storage, or you may choose from a variety of SQL DBs.