MySQLTuner is a script written in Perl that will assist you with your MySQL configuration and make recommendations for increased performance and stability.

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.

Movable Type

Domain Driven Design (Eric Evans's Patterns)

DuckDuckHack OpenSource Development Application

Interactively ping multiple hosts from one location

code for Intro to NLP at Stanford