The PunBB JumpBox provides a fully self-contained instance of the powerful PunBB forum in the time it takes to download. PunBB is a lightweight discussion forum that provides the essential features to host a thriving community without the tedious database, Web server, and application setup. It may have fewer bells and whistles than other forum applications but it has an intuitive user interface and renders XHTML-compliant output.
Devalot is a social networking application centered around software projects. It connects the user community with the development community and encourages participation and communication. It includes all the features you've come to expect in modern Web-based applications such as tagging, comments, and a wiki, as well as features you'd expect in project tracking software such as ticketing. It has features similar to some of those found in Trac, Collaboa, GForge, Mephisto, and Typo.
Blursoft MetaForum utilizes AJAX to generate a unique forum experience. Threads and posts auto-update in real time, with no refreshing required. User-based moderation ensures only the most interesting topics emerge above your viewing threshold, and private threads invite multiple users to engage in a private conversation. Complete with advanced quoting mechanisms, CSS based templates, and statistically normalized user rankings, MetaForum is a fresh, fast, efficient, and completely new perspective on forums and message boards.