Now, for some additional information you may find interesting:
Also, ROCOR and the Antiochian Orthodox Church have Western Rite parishes, and these have a system of the Hours more like the traditional Benedictine or Roman hours in terms of structure, for example, the Magnificat is sung at Vespers, and Lauds is celebrated as a separate office apart from Matins (whereas in the Eastern Orthodox liturgy, they are integrated). That being said, I really love the Byzantine Rite hours, particularly because that is where you will hear so many beautiful hymns, but I also do love the Western Rite and am glad we have it. I should add, in Europe I think the Romanian Orthodox have a small Western Rite as well, but I can’t recall, and the Oriental Orthodox Christians in Malankara, India historically had a Western Rite in Sri Lanka, which I recall was recently restored. The Syriac Orthodox liturgy has a beautiful Divine Office, although finding English celebrations of it might be challenging.
Among Oriental Orthodox churches, the Oriental Orthodox churches, the Coptic Orthodox church is the most accessible in terms of English language celebrations of the hours - the congregation will pray the First, Third and Sixth hour before every Divine Liturgy, and the Ninth, Eleventh and Twelfth as part of Vespers on Saturday night (usually), and these are a bit different than in the Eastern Orthodox or Roman Catholic church, in that a reader will assign one or more Psalms from each of these to be read quietly and simultaneously by each member of the congregation, from a list of Psalms specific to that hour; there is also a litany and a Gospel lesson for each hour. These hours are invariant, unlike their Eastern Orthodox counterparts, that is to say, they never change at all, except during Holy Week when a completely different set of Hours are used. The variable part of the Coptic Orthodox Divine Office is called the Psalmody. Especially popular is the Khiakh Psalmody, which is sung during Advent (which lasts for six Sundays in all the Eastern liturgical rites, and also in the Ambrosian Rite used by the Roman Catholics of Milan and some related liturgical rites). Psalmody is sung by the choir, and by laity who know the hymns.
Lastly, regarding attendance and feast days:
The most important and well attended feasts vary from parish to parish and include the parish feast day, and such holidays as the Nativity of the Theotokos, the Exaltation of the Cross, the Protection of the Theotokos, Christmas, Theophany (Epiphany or the Baptism of Christ), the Presentation of the Lord (known in the West as Candlemas), the Annunciation, Holy Week - particularly Great and Holy Friday, but really the whole thing, right through Pascha, the Ascension, the Holy Apostles St. Peter and Paul and the Transfiguration, Dormition (the Assumption of the Blessed Virgin Mary), most of which happen on the same days as their Roman Catholic counterparts (the exception being All Saints Day, which is on the Sunday following Pentecost, and instead of All Souls Days, there are Soul Saturdays which generally start in the pre-Lenten Sundays and continue through Lent, then take a break for Pascha and most of Eastertide, and resume the Saturday before Pentecost Sunday) and certain very popular saints, whose feast days are sometimes different than in the Roman Catholic Church, so check on this, but these saints include St. Nicholas, the Three Holy Hierarchs (St. Basil, St. Gregory the Great and St. John Chrysostom celebrated together, although they also have their own separate feasts, with St. Basil’s being on January 1st alongside the Feast of the Circumcision of our Lord as in the Roman church), and St. George the Great Martyr, St. Demetrius, St. Anthony the Great (of Egypt, the fourth century Egyptian saint), and several other prominent martyrs and confessors, and also the Holy Apostles and Evangelists.
Depending on your church, when its feast day is, and whether or not it is a cathedral (and some large churches are called cathedrals even if they are not, strictly speaking, the main cathedral of their diocese, but are rather like pro-cathedrals in the Roman Catholic Church, a bishop may attend on one of these days - bishops frequently are at their main cathedral on the most important feast days where there is not a church in their diocese where that feast is the parish feast. But bishops do try to visit all of the churches in their jurisdiction as frequently as their health and time permits, aided by retired bishops (there is no mandatory retirement age at which bishops cease to be bishops, but many bishops of important dioceses will retire if they are not well enough to travel around their diocese and celebrate the liturgy, but they will still liturgize when possible), and when a bishop is present and actively celebrating the liturgy, a longer and more beautiful form of the divine liturgy, the Hierarchical Divine Liturgy, is used, so it is particularly nice to attend when there is a bishop present, but there are some parishes where a retired bishop is the rector, for example, All Saints ROCOR in Las Vegas, so at that church you can get a hierarchical divine liturgy throughout much of the year.