CTFd is a Capture The Flag framework focusing on ease of use and customizability. It comes with everything you need to run a CTF and it's easy to customize with plugins and themes.
Awesome list of curated hacking infosec pentesting resources.
A utility that generates random VMs for security training. Give it a set of parameters in XML and it'll build vulnerable VMs for you to practice with. Uses Puppet, Packer and Vagrant to build the images.