Rapid Task Manager is a web application to make it easier to track and manage human tasks in a small organization or project (up to ~20 people). It's running on Apache Tomcat and uses Adobe Flex for the user interface.
The Floranta libraries provide components for building Rich Client Wikis using AJAX or Java. Floranta clients can be embedded in any webpage (even plain html) and allow users to leave notes, images, cards, etc on the pages. Eg: http://www.floranta.com