Programmers' Day is a holiday celebrated on the 256th Day of the year, which falls on September 13th or 12th in leap years. It is dedicated to all the programmers who create and maintain the software that powers our modern world. The number 256 is significant because the number of distinct values can be represented with an 8-bit byte, a fundamental building block of contemporary computing. Programmers' Day is a time to recognize and appreciate the hard work and innovation of programmers who have contributed to technology development.