Good Friday is the Friday immediately preceding Easter, celebrated by Christians as the anniversary of Christ's crucifixion. The name Good Friday is generally believed to be a corruption of God's Friday. Since the time of the early church, the day has been dedicated to penance, fasting and prayer.

In the Roman Catholic church, the Good Friday liturgy is composed of three distinct parts: readings and prayers, including the reading of the Passion according to St. John; the veneration of the cross; and a general communion service (formerly called the Mass of the Presanctified), involving the reception of preconsecrated hosts by the priest and faithful.

Good Friday has been observed since about 100 C. E.  Since the late fourth century, it has been associated with the crucifixion. Many churches now have mourning services from noon until 3 p.m. to symbolize Jesus' last hours on the cross. Some congregations also re-enact Jesus' procession to the cross in a ritual known as Stations of the Cross. 

In most of Europe, in South America, in the United Kingdom and many parts of the Commonwealth, and in several states of the U.S., Good Friday is a legal holiday.

Sources:  www.MSN.com, www3.kumc.edu, www.google.com