Vagrant - Virtualized development for the masses.. Looks good, you can quickly set up a development environment based on BSD or Linux via the command line - and then work with it without having to manually install a bunch of things. Basically appliance templates that can be installed via command line tool. And a whole range of systems are offered as hosts (including OSX, for example). So, for example, also a very easy way to set up a LAMP stack or something similar under OSX.