CentOS is a "distribution" with a rather unique description: it is a free (gratis) clone of a commercially-supported "distribution" with all the branding removed. Being enterprise-grade distribution means solid and well-tested; but it also means not having the latest functionality. It also means having a small enough feature set to provide commercial support in a viable manner: and that typically means choosing one technology and sticking with it. But what if you wanted your entire system to be solid, and well-tested, but want the latest features for one particular package or program? Or what if you really wanted an enterprise system, but wanted to use one of the alternate technoligies that were not selected? This is where CentOS SIGs come in. The new CentOS is still at its core a clone of an upstream enterprise distribution. But having had success with the Xen4CentOS project, which provided a version of Xen to run on CentOS 6, they have now generalized the process. This talk will talk about CentOS SIGs: the vision, the structure, what SIGs are available. We will compare and contrast them to other community distro development models like Fedora, OpenSuSE, Debian, Ubuntu, and so forth. We will also share lessons from the CentOS Virt SIG, in which a number of virtualisation and related technologies such as Xen, oVirt, Docker and others collaborate.