There is an immediate link between innovation and production centres such as laboratories, industries, institutes, states, companies, clusters or universities. These environments have captured much of academics' fascination with knowledge and creativity. However, there are other spaces where innovation also occurs: the grey areas of informality and illegality. Considered as "backyards", these areas represent a real breeding ground for innovation. Very often, the most fascinating practices emerge in these chaotic and dark areas. As a seedbed, we investigate precisely these fertile grounds for grey innovation. This means studying creativity, learning, cunning, designs and uses in contexts of informality and illegality, with the framework of user innovation and the democratization of innovation as a framework.