Euler's Disk is a scientific educational toy, used to illustrate and study the dynamic system of a spinning disk on a flat surface (such as a spinning coin). This phenomenon has been studied since Leonhard Euler in the 18th century, hence the name.
http://www.eulersdisk.com/History.pdf


The 'Hurricane Balls' consist of two ball bearings welded together - no easy task! If you spin the Hurricane Balls on a smooth surface, you can use the plastic pipe to blow at one side of the Hurricane Balls. Not only does this keeps them spinning, you can accelerate them up to incredible speeds. Speeds of 12,000 rpm have been recorded for the Hurricane Balls using a laboratory strobe light.
vysvetlenie: http://physics.stackexchange.com/questions/14346/why-do-hurricane-balls-spin-so-fast