Puppet lets you centrally manage every important aspect of your system using a cross-platform specification language that manages all the separate elements normally aggregated in different files, including users, cron jobs, and hosts, along with obviously discrete elements like packages, services, and files. Its simple declarative specification language provides powerful classing abilities for drawing out the similarities between hosts while allowing them to be as specific as necessary, and it handles dependency and prerequisite relationships between objects clearly and explicitly.
The svnmailer is a tool that is usually called by a subversion hook to submit commit notifications in various ways (at the moment: mail via SMTP or a pipe to a sendmail like program, news via NNTP, or CIA live tracker notification via XML-RPC). It is derived from the original mailer.py distributed with subversion, but should be much more consistent, more extensible, and have many more features.
BitNami LAPPStack Native Installer is an easy-to-install environment to develop and deploy PHP applications. It includes pre-configured, ready-to-run versions of Apache, PostgreSQL, PHP, and phpPgAdmin. Amazon AWS PHP SDK makes it easier to develop PHP applications that run on Amazon Web Services. The AWS PHP SDK includes the AWS PHP library, code samples, and documentation.
The Marionette Collective (mcollective) is a framework to build server orchestration or parallel job execution systems. It uses modern technologies and concepts that make it ideal for large and cloud-based infrastructures. It's specifically geared towards systems administration tasks, but can be seen as a generic framework too.
BitNami RubyStack provides a fast, easy way to develop and deploy Ruby on Rails applications. It includes Ruby, Subversion, MySQL, SQLite, ImageMagick, and several Ruby Gems, and will optionally install Apache 2.2 with rewrite and proxy support. It supports Windows, Linux, and OS X, so you can share the same Rails environment on multiple platforms.
mod_myvhost is an Apache module for dynamically configured name-based mass virtual hosting with PHP. Virtual host configurations and PHP settings are stored in a MySQL database. There is no need to have every vhost in apache's configuration file, or to restart apache after a configuration change. It is able to change PHP settings dynamically for any vhost. By default, it sets open_basedir as the vhost's rootdir, but you can change almost any parameter that exists in php.ini. For example, you can turn on safe_mode or register_globals for a particular vhost.