Some info from http://en.wikipedia.org/wiki/Euler’s_Disk
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), and has been the subject of a number of scientific papers. This phenomenon has been studied since Leonard Euler in the 18th century, hence the name.
The disk, when spun on the mirror, exhibits a spinning/rolling motion (or spolling, a blend of “spin” and “roll”), slowly moving through different rates and types of motion before coming to rest.
The spinning/rolling disk ultimately comes to rest; and it does so quite abruptly, the final stage of motion being accompanied by a whirring sound of rapidly increasing frequency