If you are fortunate enough to live near a church which has Tenebrae, I encourage you to go. I miss this special Holy Wednesday service, which begins with a procession of lit candles and proceeds through the singing of the Lamentations of Jeremiah, with a candle being extinguished until the entire church is in darkness. Then, the congregation takes the hymnals and bangs them on the pews to create the sound of the earthquake which happened when Christ died.
Tenebrae means shadow or darkness. The ancient form was, as this note from Catholic Encyclopedia states, On the three days before Easter", says Benedict XIV (Institut., 24), "Lauds follow immediately on Matins, which in this occasion terminate with the close of day, in order to signify the setting of the Sun of Justice and the darkness of the Jewish people who knew not our Lord and condemned Him to the gibbet of the cross."
The simplicity of the service, which is only a meditation on the Death of Christ, is a fitting beginning to the grand liturgies of the Triduum.
"How doth the city sit solitary that was full of people; How is the mistress of the Gentiles become as a widow; the princess of provinces made tributary! Weeping she hath wept in the night, and her tears are on her cheeks. There is none to comfort her among all them that were dear to her: all her friends have despised her, they are become her enemies."
Several of the Psalms are also sung, with some readings from St. Augustine on the Psalms.
"Think not, therefore, that the wicked are in this world without a purpose, and that God worketh no good out of them. Every wicked man liveth, either that he many himself be corrected, or that through him some good man may be exercised."