Just a reminder that this day is a holy day of obligation for Catholics. A few dioceses I have heard seem to have removed the obligatory nature of this feast for Catholics in those dioceses. I perused a number of diocesan Web sites and from cursory searches was unable to ascertain whether those dioceses list the feast as obligatory. Mass confusion! This is something that diocesan staff need to work on this coming year for the New Evangelization (and there are many causes for hope, seeing so many dioceses Tweeting). If you are unsure, go to Mass!
Below is the Latin and English of the Veni Creator Spiritus (Come Holy Ghost) from this great Latin site. Below the words of the solemn prayer is the hymn sung in Latin and then English. By the way, there is no real difference in saying "Holy Spirit" or "Holy Ghost"; spirit as you can see is more Latin in origin (meaning "breath"); ghost is more Germanic (from geist, which means "spirit"). Both are perfectly acceptable forms of prayer.
Veni Creator Spiritus—Latin
Come Holy Ghost—English
Veni, Creator Spiritus,
mentes tuorum visita,
imple superna gratia
quae tu creasti pectora.
Come, Holy Ghost, Creator blest,
and in our souls take up Thy rest;
come with Thy grace and heavenly aid
to fill the hearts which Thou hast made.
Qui diceris Paraclitus,
altissimi donum Dei,
fons vivus, ignis, caritas,
et spiritalis unctio.
O comforter, to Thee we cry,
O heavenly gift of God Most High,
O fount of life and fire of love,
and sweet anointing from above.
Tu, septiformis munere,
digitus paternae dexterae,
Tu rite promissum Patris,
sermone ditans guttura.
Thou in Thy sevenfold gifts are known;
Thou, finger of God's hand we own;
Thou, promise of the Father, Thou
Who dost the tongue with power imbue.
Accende lumen sensibus:
infunde amorem cordibus:
infirma nostri corporis
virtute firmans perpeti.
Kindle our sense from above,
and make our hearts o'erflow with love;
with patience firm and virtue high
the weakness of our flesh supply.
Hostem repellas longius,
pacemque dones protinus:
ductore sic te praevio
vitemus omne noxium.
Far from us drive the foe we dread,
and grant us Thy peace instead;
so shall we not, with Thee for guide,
turn from the path of life aside.
Per te sciamus da Patrem,
noscamus atque Filium;
Teque utriusque Spiritum
credamus omni tempore.
Oh, may Thy grace on us bestow
the Father and the Son to know;
and Thee, through endless times confessed,
of both the eternal Spirit blest.
Deo Patri sit gloria,
et Filio, qui a mortuis
surrexit, ac Paraclito,
in saeculorum saecula.
Now to the Father and the Son,
Who rose from death, be glory given,
with Thou, O Holy Comforter,
henceforth by all in earth and heaven.
Oh, and don't forget that one can pray that the plenary indulgence be applied to a soul in purgatory.