http://www.google.com.mx/logos/aztecsunstone09.gif

<<The Aztec calendar stone, Mexica sun stone, or Stone of the Sun (Spanish: Piedra del Sol), is a large monolithic sculpture that was excavated in the Zócalo, Mexico City's main square, on December 17, 1790.>>

http://en.wikipedia.org/wiki/Aztec_sun_stone

One of the cooler looking logos I think...