Mark Rehorst has an excellent set of instructions on how to build your own Van de Graaff generator. What’s that, you say? Well, a Van de Graaff generator is a device capable of producing high voltages by collecting electrostatic charges on a large metal sphere. Basically, its a fun and relatively safe way of creating high voltages, which can then be used to do things like make peoples hair stand up, or power particle accelerators.