I was watching some show on Ancient Egypt, and yet another unexplained object was mentioned. This is called the ‘Schist Bowl’ (named for the rock it is fashioned from) and it is currently housed in the Cario Museum. The disc was found in the Mastaba of Sabu in 1936 by Egyptologist Water Brian Emery.
It is unknown what it was used for (oil lamp, propeller, bowl, etc), but it is very un-Egyptian in style- and the crafting is very unusual for something made 5000+ years ago.
Some very good information on the tomb can be found on Bibliotecapleyade and S8int.com has a page of info for the disc on one of it’s Out of Place Artifacts page. I also found another article on the disc via Epoch Times.
Kind of reminds me of the enigma of the Dropa Stone Discs (found in 1938 by Dr. Chi Pu Tei).