Airborne wind energy is the attempt to bring the digital revolution to the production of energy. It means that we convert the power of high-altitude winds into electricity by autonomously controlled aircraft which are connected to the ground via a tether. This technology can be a key element to finally power the world by clean energy only. In this talk we will explain the physical foundations, give an overview of the current status and show you how to build an experimental system by yourself: it involves hacking an off-the-shelf model aircraft and its autopilot based on the open and free Ardupilot framework.