Chef

Chef is an infrastructure automation tool written in Ruby that operates similarly to Puppet.

The administrator writes "recipes" that describe the status that each node administered by Chef should have (deployment of configuration files, packet installation, password management, etc.). Chef then applies those recipes to the different nodes, enabling the centralised administration of a large number of different machines.
Chef has a younger user community than Puppet, but one that appears very promising. Moreover, many of the ideas introduced by Chef have also been included in Puppet.
Chef is distributed under the Apache License.