AfterLogic WebMail Lite PHP is a free AJAX webmail application. Users can receive, view, manage, compose, and send email through web interface (IMAP and SMTP supported). Source code included.
A plugin for Gaim which diverts incoming IMs to email when you're away. This project is dead (http://bayleshanks.com/pamv1).
TikeIRCd is a IRC daemon written in perl. It is based off of the long deceased perl-ircd (here on Sourceforge) and is compliant with the TS6 protocol.