“Celt” is a term that archaeologists use for various kinds of stone objects found in excavations of Celtic and other early civilization sites. Their original purpose is unknown. Some of them have the novel feature that when spun on a smooth flat surface they have a preferred spin direction. Beginning at the end of the 19th century, physicists, artists, artisans and others have designed many variations on this dynamical object. Here we present a short overview of some of these, including a new one designed by the author during the past year. It is called the “DeltaCELT” (or “δCELT”) and its design incorporates the Feigenbaum dynamical constant δ ~ 4.6692...