On the 23rd December in the illustrious Sarum rite, and many other local rites and uses, the last of the Great 'O' Antiphons on December 23rd was not O Emmanuel as in the Roman rite, but O Virgo virginum. This meant that 'O Sapientia' instead of being sung on December 17th was sung on December 16th. A vestige of this practice can be found in the 1662 Book of Common Prayer which, although not providing texts, indicates 'O Sapientia' in the Kalendar on the 16th December.
The interesting website The Hymns and Carols of Christmas gives the texts and other information for O Virgo virginum and several other, less commonly occurring, 'O' antiphons from different sources.
O Virgo virginum, quomodo fiet istud? quia noc primam similem visa es, nec habere sequentem. Filæ Jerusalem, quid me admiramini? Divinum est mysterium hoc quod cernitis.
O Virgin of virgins! how shall this be? for never was there one like thee, nor will there ever be. Ye daughters of Jerusalem, why look ye wondering at me? What ye behold, is a divine mystery.
Dom Guéranger notes that this antiphon was used in the post-Tridentine Roman rite in Spain and some of her Dominions for the pro aliquibus locis feast of the Expectation of the BVM on 18th December. The old practice of having the antiphon on the 23rd seems to me at least an excellent one emphasising the inseparable link between the Mother of God and the mystery of the Incarnation. A beautiful acrostic was created (very common in the Sarum breviary) by taking the first letter of each antiphon in reverse order. So for the seven in the Roman Breviary this creates 'Ero Cras' which translates as 'Tomorrow, I will come'. With the addition of O Virgo virginum this becomes 'Vero Cras', 'Truly, tomorrow'.
'YouTube' has several video recordings. A plainsong one:
For a rather pleasing polyphonic version:
There were also other 'Lesser O's' (again texts from the excellent site of Doug Anderson noted above):
O Hierusalem, civitas Dei summi: leva in circuitu oculos tuos, et vide Dominum tuum, quia jam veniet solvere te a vinculis.
O Jerusalem, city of the great God: lift up thine eyes round about, and see thy Lord, for he is coming to loose thee from thy chains.
O Rex pacifice, Tu ante saecula nate: per auream egrede portam, redemptos tuos visita, et eso illuc revoca unde ruerunt per culpam.
O King of peace, that was born before all ages: come by the golden gate, visit them whom thou hast redeemed, and lead them back to the place whence they fell by sin.
O Gabriel, nuntius caelorum, qui clausis ianuis ad me introisti, et verbum annuntiasti: concipies et paries Emmanuel vocabitur.
O Gabriel! the messenger of heaven, who camest unto me through the closed doors, and didst announce the Word unto me : Thou shalt conceive and bear a Son, and he shall be called Emmanuel.
In the Roman rite the set of antiphons De Sion etc are sung at Lauds and the Hours. At Lauds the antiphon on the Benedictus is special to the 23rd December: Ecce completa sunt. The ferial preces are sung at Lauds and the Hours. Mass is celebrated after None and is of the preceding Sunday without the Alleluia and its verse. The second collect is Deus, qui de beate, the third collect Ecclesiae. The dismissal is Benedicamus Domino. At Vespers O Emmanuel is sung. The ferial preces are sung kneeling.