CoreOS
CoreOS is an extremely lightweight base OS for Docker. It installs just a kernel, systemd and docker, and then you use Docker to pull in any service that you want. Can be used as a base OS when running your own PaaS with Docker, or other kind of deployments.
linux open-source commercial virt cloud-paas
Netboot.xyz
Netboot.xyz is a preconfigured iPXE bootloader that completely eliminates the need for large ISO files for a vast range of operating systems.
linux windows osx bsd solaris open-source free commercial provisioning virt
Review Board
Review Board is a feature packed code review tool for multiple SCM systems (like git, bzr, cvs, subversion, etc).
linux open-source commercial scm python