The Divine Liturgy is the Eucharistic service of the Orthodox Church. In parishes it is celebrated on Sunday mornings and often on many Feast days. Because the Divine Liturgy includes the consecration of the Holy Eucharist, it may only be celebrated by an ordained priest (or Bishop) of the Church. There are two forms of the Divine Liturgy in common use in the Orthodox Church, the Liturgy of St. John Chrysostom and the Liturgy of St. Basil the Great. These liturgies retain essentially the same form they had when composed over 1500 years ago. The Divine Liturgy usually lasts 90 minutes to two hours.
Vespers is an evening prayer service, usually held around 6 p.m. to 7 p.m. in parishes. Most parishes will hold Vespers on Saturday evening (or the eve of a Feast) to prepare yourself for the Divine Liturgy with prayer, psalms and hymns. Vespers may be led by a priest or a lay leader may offer a Reader's Vespers service. Vespers usually last 30 - 45 minutes.
Matins is the morning prayer service and is usually offered before the Divine Liturgy on Sunday mornings. Matins lasts about one hour.
The Typica service is held in place of the Divine Liturgy if no priest is available to serve the parish. The Typica includes many of the hymns and readings from the Divine Liturgy, but does not have a Eucharistic component. The Typica can be led by a Reader, Deacon or even a lay member who has been blessed by the Bishop to offer the service. There is no homily given, but the service will often include readings from homilies of the Church Fathers that are relevant to the Scripture readings for the day. The Typica service lasts about 45 minutes.
Prayer of the Hours
The Orthodox Horologion includes specific prayers for the different hours of the day. Parishes often precede the Divine Liturgy with the reading of 3rd and 6th Hour prayers. Each "Hour" takes about 10 minutes to complete.