Vagrant is a tool for building and distributing development environments.

Puppet, an automated configuration management tool

A systems integration framework, built to bring the benefits of configuration management to your entire infrastructure.

Ruby DSL based software provisioning tool

Sprinkles for Apache, Passenger, Memcached, Git, Mysql or Postgres

See http://github.com/pitluga/supply_drop

Rudy: Not your grandparents' EC2 deployment tool.

Easy Ubuntu server setup via teleportation.

ESX Support for Chef's Knife Command

AutomateIt is an open source tool for automating the setup and maintenance of servers, applications and their dependencies.

Boris: A networked-device scanning library. Boris allows you to write programs for logging into and pulling information off of various server platforms, appliances, and other types of networked devices, producing clean and consistent data ideal for configuration managment usage.

Test-driven sysadmin.