I say that because you have the chance to experience this amazingly beautiful service — surely Holy Mother Church's most sublime non-Mass liturgy — for the first time tomorrow (Spy Wednesday) night at 7:30. [Get directions to SJC here.)
The office of Tenebrae:
...contains 14 psalms, 9 readings, and one canticle, the Benedictus (Song of Zechariah). Lighting is gradually reduced throughout the service. Initially 15 candles are lit and are placed on a special stand known as a hearse, which are extinguished one by one after each psalm. The last candle is hidden beneath the altar, ending the service in total darkness. In some places the use of a strepitus (Latin for "great noise") is included as part of the service. The great noise is usually generated by slamming a book closed, banging a hymnal or breviary against the pew, or stomping on the floor, symbolizing the earthquake that followed Christ's death. This custom seems to have originated as a simple signal to depart in silence. Following the great noise a single candle, which had been hidden from view is returned to the top of the hearse. It is felt that the single candle signifies the return of Christ to the world with the Resurrection.
At the conclusion of the SJC Tenebrae service, when the church is in total darkness but before the strepitus, the choir sings Allegri's hauntingly beautiful Miserere — the hearing of which is, for me personally, the high point of Lent.