Mole Day is an unofficial holiday celebrated among chemists in America on October 23, between 6:02 am and 6:02 PM, making the date 6:02 10/23 in the American way of writing out dates. The time and date are derived from Avogadro's number, which is approximately 6.022x10^23, defining the numer of particle (atoms or molecule) in a mole, one of the seven basic SI units.
Many high schools around the United States celebrate Mole Day as a way to get their students interested in chemistry.