I’d probably start designing and building a rolling ball clock/ sculpture, then hit some sort of obstacle and switch to making a self recirculating eddy current tube, get frustrated and try to design and build an electronically commutated counter rotating propeller driver, get frustrated and try to build a garage sized 3d printer, get frustrated and try to build a delayed action door closer get frustrated and try to build a co-planar compound cycloidal reducer, get frustrated and then forget my wife’s anniversary until 4pm the day before.