Blueprint - create install recipes from existing servers.
Spotted this while faffing around duplicating a Rails install.
It's similar to Puppet in that it allows you to deploy a similarly configured server based on a template. However, the really cool part is that you can build a template from an existing server without a lot of faffing. You can also use it to build the templates in formats Chef and Puppet can use.
Works on Red Hat and Debian based OS only, according to the docs.