The Mass itself is the unbloody repetition of Calvary. The priest, and victim of the sacrifice are the same person, Jesus, at both Calvary and every Mass. From the earliest days, Good Friday has been kept as an aliturgical day, that is one on which we do not have the Liturgy celebrated. In the past there were more in the Latin Church. In the East there are many days where the Liturgy is not celbrated, and like our Good Friday they have the Liturgy of the Pre-Sanctified, where the initial rites of the Liturgy and the Pater (our Father) and communion are observed with the Blessed Sacrament that has been consecrated on a previous day.

It stands out more as an oddity for us in the Latin Rite, because we only have one official aliturgical day. On Good Friday we deprive ourselves of the Mass and reflect on what a solemn and extraordinary event happened on Calvary that day. The practice is described in the Catholic Encyclopedia in this manner.

[quote:1kt8b5cn]It is merely the Communion separated from the liturgical celebration of the Eucharist properly so called. The details of the ceremony are not found earlier than in books of the eighth or ninth century, but the service must belong to a much earlier period. At the time when synaxes without liturgy were frequent, the ‘Mass of the Presanctified’ must have been frequent also. In the Greek Church it was celebrated every day in Lent except on Saturdays and Sundays, but in the Latin Church it was confined to Good Friday.[/quote:1kt8b5cn]
So in summary, it is a very ancient practice of the Church, in the West we only see it on Good Friday, but before it was more frequent. If I find anything else, I’ll try to post it.