Here's a list of the stuff we have running on the SpamAssassin zone, zones spamassassin.zones.apache.org and spamassassin2.zones.apache.org:
PreflightBuildBot: continuous integration daemon, running at http://buildbot.spamassassin.org:8011 . It uses Python and the Twisted framework, which is installed in /local. It tests our rulesets against a small corpus of mail on every SVN checkin.
RuleQaApp: web application aimed at QA'ing and developing rules (spamassassin2.zones.apache.org)
rsync.spamassassin.org, an rsync server with several authenticated accounts for upload of nightly MassChecks results and those for the periodic rescoring run.