firelight
firelight was originally built for my family, so we could stay in touch and share pictures and events easily in a private setting. Features include a calendar, photo galleries, news, a group emailer, and guest access. Built in PHP and the jQuery javascript library.
firelight is open source, and will install easily on a standard LAMP installation with PHP 5. SVN repositories are hosted at Google Code. Please contact me if you are interested in contributing to this project.