So, one of the Psalms tell us to pray seven times a day. The Divine Office, or Liturgy of the Hours, of old used to have eight prayer times: Matins (prayed in the middle of the night, also called Vigils, I believe), Lauds (prayed at sunrise), Prime (to be prayed at the first hour after the rising of the Sun), Terce (the third hour), Sext (the sixth hour), None (the ninth hour), Vespers (evening) and Compline (before you go to bed). The new D.O. has taken the four Little Hours--Terce, Prime, Sext and None-- and compressed them into three. Matins is now called the Office of Readings, Lauds is now called Morning Prayer, the little hours are now called Midmorning, Noontime, and Midafternoon prayer, Vespers is called Evening Prayer and Compline is called Night Prayer.
When you do the Office, just as in the Mass, there are two parts that you have to keep track of: the Ordinary (the part that does not change ever) and the Propers (the part that changes with the season). However, in the Office, there is a third part you have to keep track of, which is the Psalter. In the new Liturgy of the Hours (probably the one you would be using), there is a four-week Psalter. Monastic communities are allowed to do their own thing, and some of them stick with the old practice of praying all the Psalms in a week or even a day, but the current Liturgy of the Hours allows you to pray all the Psalms (except the cursing Psalms, which they have omitted) in four weeks.
