The Divine Office during the Sacred Triduum, which is identical in the (modern) Benedictine and Roman Rites, is quite differently structured to that of the rest of the year. And the high point of those three days is surely the Office of Tenebrae, Matins and Lauds, sung in the darkness.
The psalms of Tenebrae very much trace the Church's take on the events of the Triduum, and so make a great source of Lenten meditation. And of course, if you are going to in or attend this office, useful to get a flavour of the psalms involved by way of preparation.
The Office of Tenebrae is structured into three Nocturns of three psalms each (Matins), followed by (in the post-1911 version of the hour) five psalms (one of which is a canticle, or psalm from outside the book of psalms) for Lauds. In addition each of the Nocturns has three readings and a responsory (not covered here), and the Benedictus is sung with an antiphon at Lauds. The Office ends with the antiphon Christus factus est pro nobis, with an additional phrase being added each night.
This series of posts on that Office was originally presented for Lent 2013. The first post was an Introduction to the series. An asterix indicates a psalm that is repeated on one or more occasions (only one post per psalm has been provided on these).
Canticle: Exodus 15
Canticle of Habaccuc
Canticle: Isaiah 38
In the older version of Tenebrae, now restored in some places, the psalms of Lauds were as follows:
Thurs: Ps 89; Fri: Ps 142; Sat: Ps 42
OT canticle - Thurs: Ex 15; Fri: Hab 3; Sat: Is 38