VoiceChatter is a free, open source, and cross platform voice chat application. It is built for gaming, so it is light weight, yet delivers excellent voice quality over minimal bandwidth and latency. For more, visit http://www.voicechatter.net
A light-weight, web-based event information tracking application implemented in Java and Ruby. Development is done using Extreme Programming (XP) practices and includes both jUnit & FitNesse testing.
This is a complete Messaging system, having simple online/offline messaging and task management. It has a very light weight server. A GNOME/GTK+ client is also provided. The server uses mysql. plans are underway to allow for a LDAP server to be used.