The Liturgy of the Hours, also called the Divine Office, is a collection of Psalms and readings from the Bible that every priest and religious prays on a daily basis.
Lay people are encouraged to pray the Divine Office on their own, but they can also join priests at their local parish when it is offered.
Advice from a saint
St. Francis de Sales praised this custom in his Introduction to the Devout Life:
[M]y daughter, you should endeavor to assist at the Offices, Hours, Vespers, etc., as far as you are able, especially on Sundays and Festivals, days which are dedicated to God, wherein we ought to strive to do more for His Honor and Glory than on others.
He then pointed to St. Augustine, who was touched by the Divine Office early in his conversion:
You will greatly increase the fervor of your devotion by so doing, even as did St.. Augustine, who tells us in his Confessions, that in the early days of his conversion he was touched to the quick, and his heart overflowed in happy tears, when he took part in the Offices of the Church.
While lay people can pray on their own, St. Francis de Sales strongly suggested the act of praying with other people.
Moreover (let me say it here once for all), there is always more profit and more consolation in the public Offices of the Church than in private acts of devotion, God having willed to give the preference to communion in prayer over all individual action.
Very few parishes offer this as an option to parishioners, but it may be a simple way that priests can fulfill their daily obligation, while also encouraging more lay people to pray the Liturgy of the Hours.
