Good Friday is a Christian holiday commemorating the crucifixion of Jesus and his death at Calvary. It is observed during Holy Week as part of the Paschal Triduum on the Friday preceding Easter Sunday, and may coincide with the Jewish observance of Passover. It is also known as Holy Friday, Great Friday, Great and Holy Friday (also Holy and Great Friday), and Black Friday.
Members of many Christian denominations, including the Catholic, Eastern Orthodox, Lutheran, Anglican, Methodist, Oriental Orthodox and Reformed traditions, observe Good Friday with fasting and church services. Communicants of the Moravian Church have a Good Friday tradition of cleaning gravestones in Moravian cemeteries.
The date of Good Friday varies from one year to the next on both the Gregorian and Julian calendars. Eastern and Western Christianity disagree over the computation of the date of Easter and therefore of Good Friday. Good Friday is a widely instituted legal holiday around the world, including in most Western countries and 12 U.S. states. Some countries, such as Germany, have laws prohibiting certain acts, such as dancing and horse racing, that are seen as profaning the solemn nature of the day. (Source)