Hosting git repositories -- Gitolite allows you to setup git hosting on a central server, with very fine-grained access control and many (many!) more powerful features.

Auto-builds and tests all the branches of your git projects, showing pass/fail results on a web page/RSS feed. Isolates failures to the first commit that caused the problem.

a nagios module for puppet

Perl extension for generating test monitoring configurations (nagios/icinga/shinken)