The AbsTemplate is an extremely simple and lightweight template engine for PHP. It consists only of one file: the base class. You can set your own custom delimiters for variables to use inside template files, use any type of templates you want (that is, the template files can have any extension you want (be it .php, .inc, .tpl, etc...)), display multiple templates per page, cache templates, and choose to assign the content of a template to a variable and, when appropriate, just display its content.
Address Book Continued is a multi-user address book Web application. It also makes use of AJAX, which means that page reloads only happen on login/logout; the rest of the operations is handled asynchronously in the background. It's well usable, even over slow connections. You can even install ABC on your desktop PC and configure it so that it doesn't require login for connections coming from the local computer.
Agilefant is a backlog management system that can be used when spreadsheets and most of the current issue tracking and project management systems meet their limits. It is intended to be used with agile methodologies that emphasize building releasable software in short, fixed time periods, where features are commonly managed using "backlogs".