The fifth Sunday of Lent, a Sunday of the first class, not permitting the celebration of any feast, no matter of what rank, but allowing a commemoration of feasts which are not transferred. It is called Dominica de Passione in the Roman Missal, and Dominica Passionis in the Breviary. Durandus and other liturgical writers speak of it as Dominica in Passione, or simply Passio, or Passio Domini. It is also known as Judica Sunday, from the first word of the Introit of Mass; Isti sunt, from the beginning of the first response in the Matins; Octava mediana, it being the eighth day after Laetare Sunday, called sometimes Mediana, or Middle of Lent; Repus, an abbreviation of repositus, i.e. absconditus, or hidden from the veiling of the Crosses (Du Cange, "Glossar." s. v. repositus). Among the Slavs it is the Nedela strastna (pain, suffering, terrible), muki (painful, or sorrowful), gluha (deaf or silent), tiha (quiet), smertelna (relating to death), or also cerna (black), which appellation is also found in some parts of Germany as Schwartzer Sonntag. Since after this Sunday there are not many more days of the Lenten season the Greek Church admonishes the faithful to special mortifications, and places before them the example of the penitent St. Mary of Egypt. - Catholic Encyclopedia

As an historical aside the exact Mass propers for today (extraordinary form) are present in the ancient Gregorian Sacramentaries of the early Church which I find to be pretty cool.

Mass Propers

Introit
Judge me, O God, and distinguish my cause from the nation that is not holy: deliver me from the unjust and deceitful man: for Thou art my God and my strength. -- (Ps. 42. 3). Send forth Thy light, and Thy truth: they have conducted me, and brought me unto Thy holy hill, and into thy tabernacles... -- Judge me, O God, and distinguish my cause...

Collect
We beseech Thee, O almighty God, look mercifully upon Thy family: that, by Thy bounty, it may be governed in body, and by Thy keeping be guarded in mind. Through our Lord Jesus Christ, Thy Son, who liveth and reigneth with Thee...

Epistle
Brethren, Christ being come, as High Priest of the good things to come, by a greater and more perfect tabernacle, not made with hands, that is, not of this creation: neiher by the blood of goats or of calves, but by His own Blood, entered once into the Holies, having obtained eternal redemption. For if the blood of goats and of oxen and the ashes of a heifer, being sprinkled, sanctify such as are defiled, to the cleaning of the flesh: how much more shall the Blood of Christ, who, by the Holy Ghost, offered Himself unspotted unto God, clease our conscience from dead works, to serve the living God? And therefore He is the Mediator of the new Testament: that by means of His death, for the redemption of those transgressions which were under the former Testament, they that are called may receive the promise of eternal inheritance, in Christ Jesus our Lord.

Gradual
Deliver me, O Lord, from my enemies: teach me to do Thy will. V.: (Ps. 17, 48, 49). Thou art my deliverer, O Lord, from the angry nations: Thou wilt lift me up above them that rise up against me: from the unjust man Thou wilt deliver me.

Tract
Often have they fought against me from my youth. V.: Let Israel now say: often have they fought against me from my youth. V.: But they could not prevail over me: the wicked have wrought upon my back. V.: They have lengthened their iniquities: the Lord who is just will cut the necks of sinners.

Gospel
At that time Jesus said to the multitudes of the Jews: Which of you shall convince Me of sin? If I say the truth to you, why do you not believe Me? He that is of God heareth the words of God. Therefore you hear them not, because you are not of God. The Jews therefore answered and said to Him: Do not we say well, that Thou art a Samaritan, and hast a devil? Jesus answered: I have not a devil: but I honor My Father, and you have dishonored Me. But I seek not My own glory: there is One that seeketh and judgeth. Amen, amen, I say to you: If any man keep My word, he shall not see death for ever. The Jews therefore said: Now we know that Thou hast a devil. Abraham is dead, and the Prophets: and Thou sayest: If any man keep My word, he shall not taste death for ever. Art Thou greater than our father Abraham, who is dead? and the prophets are dead. Whom dost Thou make Thyself? Jesus answered: If I glorify Myself, My glory is nothing: it is My Father that glorifieth Me, of whom you say that He is your God, and you have not known Him: but I know Him: and if I shall say that I know Him not, I shall be like to you, a liar. But I do know Him, and do keep His word. Abraham your father rejoiced that he might see My day: he saw it and was glad. The Jews therefore said to Him: Thou art not yet fifty years old: and hast Thou seen Abraham? Jesus said to them: Amen, amen, I say to you, before Abraham was made, I am. They took up stones therefore to cast at Him: but Jesus hid Himself, and went out of the temple.

Offertory
I will confess to Thee, O Lord, with my whole heart: render to Thy servant: I shall live and keep Thy words: enliven me according to Thy word, O Lord.

Secret
May these gifts, we beseech Thee, O Lord, both loose us from the bonds of our wickedness, and win for us the gifts of Thy mercy. Through our Lord Jesus Christ, Thy Son, who liveth and reigneth with Thee in the unity of the Holy Ghost...

Preface
It it truly meet and just, right and for our salvation, that we should at all times, and in all places, give thanks unto Thee, O holy Lord, Father almighty, everlasting God; Who didst establish the salvation of mankind on the tree of the Cross; that whence death came, thence also life might arise again, and that he, who overcame by the tree, by the tree also might be overcome: Through Christ our Lord. Through whom the Angels praise Thy Majesty, the Dominations worship it, the Powers stand in awe. The Heavens and the heavenly hosts together with the blessed Seraphim in triumphant chorus unite to celebrate it. Together with these we entreat Thee that Thou mayest bid our voices also to be admitted while we say with lowly praise:

Communion
This is My Body which shall be delivered for you: this chalice is the new Testament in My Blood, saith the Lord: do this, as often as you receive it, in commemoration of Me.

Postcommunion
Remain with us, O Lord, our God, and defend with Thy continual support those whom Thou hast renewed by Thy Mysteries. Through our Lord Jesus Christ, Thy Son, who liveth and reigneth with Thee in the unity of the Holy Ghost...

From a Sermon by Pope Saint Leo the Great

Among all the solemn feasts which are kept by Christians, we are well aware, dearly beloved, that the paschal mystery holdeth first place. The observances of all the year are ordered to the end of preparing us to celebrate duly and worthily this one mystery. But the days which have now come upon us make an especial claim on our devotion, seeing that they are those which be in immediate preparation for that most glorious mystery of the divine mercy. The holy Apostles themselves (taught doubtless by the Holy Ghost) ordered a strict fast to be kept on these days, that by sharing together Christ's Cross with him, we too may in some measure partake in what he did for our sake, as the Apostle saith : We are the children of God, if so be that we suffer with him, that we may be also glorified together. He that is partaker of the sufferings of the Lord hath a sure and certain hope of that blessedness which he hath promised unto us.

To no one, no matter what be the circumstances of his life, dearly beloved, is denied a share in this glory of partaking in Christ's sufferings, as if times of calm were without their occasions of exercising strength. The Apostle giveth us this warning : All that will live godly in Christ Jesus shall suffer persecution. Therefore, so long as godliness is not lacking, neither is persecution lacking. The Lord himself saith in one of his own exhortations : He that taketh not his cross, and followeth after me, is not worthy of me. And we must not doubt that these words of Christ apply not only to his immediate disciples, to whom he spake them, but belong to all the faithful and to the whole Church. For the Church in the person of believers which were present and heard these words, believed and heard on behalf of all them who would afterwards accept the way of salvation in the Church.

As then, it is the duty of the whole body of the Church to live godly, so also it is the duty of all times to be a-bearing of the Master's Cross, and that not only in the mystical body in general, but individually in the person of each member thereof, who each and every one supporteth the weight of the Cross in his own way and measure. The one common name for all their carrying of the Cross is persecution, but the manner of suffering is special to each. Now there is often more danger from a foe lurking in ambush than from the open enemy. Blessed Job, who was well tried in this world by alternate changes of good and evil, said devoutly and truly : Is there not an appointed time to man upon earth? That is, Is not man's life appointed as a time of trial? The attack upon the faithful soul cometh not alone in bodily pains and suffering. For if the health of the bodily members be sound, often the soul is grievously sick of longing for fleshly indulgence. But since the flesh lusteth against the spirit, and the spirit against the flesh, the rational mind must be disciplined by the carrying of the Cross on such wise that, albeit the soul is enticed by evil desires, the will refuseth to give consent, by reason of the piercing of the nails of continence and the fear of God.

From a Homily by Pope Saint Gregory the Great

Dearly beloved brethren, consider the gentleness of God. He came to take away sin, and he saith : Which of you convinceth me of sin? He, who in virtue of his Godhead was able to justify sinners, did not disdain to shew by an appeal to reason that he was not himself a sinner. But verily the words which he addeth are exceeding awesome : He that is of God heareth God's words, and if one who is not of God, is not able to hear God's words, let each one ask himself : Do I, in the ear of my heart, hear God's words, and understand whose words they are? The Truth commandeth us to long for a fatherland in heaven, to bridle the lusts of the flesh, to turn away from the glory of the world, to covet no man's goods, and to bestow freely of our own.

Let each of you, therefore, think within himself if this voice of God soundeth loud in the ear of his heart ; for thereby will he know whether he be of God. Some there be, whom it pleaseth not to hear the commandments of God, even with their bodily ears. And some there be, who receive the same with their bodily ears, but whose heart is far from them. And some also there be, who hear the words of God with joy, so that they are moved thereby even to tears. But when their fit of weeping is past they turn again to iniquity. They who despise to do the words of God certainly cannot be said to hear them. Wherefore, dearly beloved brethren, call up your own life before your mind's eye, and then ponder with trembling those awful words which the mouth of the Truth spake : Ye therefore hear them not, because ye are not of God.

The Truth speaketh these words concerning the reprobate. But the reprobate make manifest the same thing concerning themselves, by their evil deeds. Thus immediately followeth : Then answered the Jews, and said unto him : Say we not well that thou art a Samaritan, and hast a devil? Hear now what the Lord saith to so great an insult : I have not a devil, but I honour my Father, and ye do dishonour me. The Lord said : I have not a devil. But he did not say : I am not a Samaritan. For in a sense a Samaritan he was indeed, since the word Samaritan is by interpretation a Watcher, and the Lord is that Watcher, of whom the Psalmist saith, that except he keep the city, any other watchman waketh but in vain. He also is that Watchman unto whom crieth Isaiah : Watchman, what of the night, Watchman, what of the night? Wherefore the Lord did not say : I am not a Samaritan. But : I have not a devil. Two charges were brought against him. One he denied. To the other his silence gave assent.

V. Tu autem, Dómine, miserére nobis.
R. Deo grátias.