Unetanah Tokef is one of the the central piyyut of Rosh Hashanah. It presents us before God, the merciful judge, on this "awesome and terrible day," asking what each of our fates will be and asking that "repentance, prayer and righteousness avert the severe decree." Because of it's apocalyptic tone and vision, the Unetanah Tokef has always been a source for Jewish legends and poetry. (MyJewishLearning.com presents a wonderful legend about Rabbi Amnon of Mainz as one example).
Here is the full text (from MyJewishLearning.com) followed by the contemporary musician and poet Leonard Cohen performing his "Who By Fire."
We shall ascribe holiness to this day.
For it is awesome and terrible.
Your kingship is exalted upon it.
Your throne is established in mercy.
You are enthroned upon it in truth.
In truth You are the judge,
The exhorter, the all‑knowing, the witness,
He who inscribes and seals,
Remembering all that is forgotten.
You open the book of remembrance
Which proclaims itself,
And the seal of each person is there.
The great shofar is sounded,
A still small voice is heard.
The angels are dismayed,
They are seized by fear and trembling
As they proclaim: Behold the Day of Judgment!
For all the hosts of heaven are brought for judgment.
They shall not be guiltless in Your eyes
And all creatures shall parade before You as a troop.
As a shepherd herds his flock,
Causing his sheep to pass beneath his staff,
So do You cause to pass, count, and record,
Visiting the souls of all living,
Decreeing the length of their days,
Inscribing their judgment.
On Rosh Hashanah it is inscribed,
And on Yom Kippur it is sealed.
How many shall pass away and how many shall be born,
Who shall live and who shall die,
Who shall reach the end of his days and who shall not,
Who shall perish by water and who by fire,
Who by sword and who by wild beast,
Who by famine and who by thirst,
Who by earthquake and who by plague,
Who by strangulation and who by stoning,
Who shall have rest and who shall wander,
Who shall be at peace and who shall be pursued,
Who shall be at rest and who shall be tormented,
Who shall be exalted and who shall be brought low,
Who shall become rich and who shall be impoverished.
But repentance, prayer and righteousness avert the severe decree.
Leonard Cohen - Who By Fire