Plenary Indulgence

A plenary indulgence is obtainable under the usual conditions today by reciting the Pentecost vespers hymn Veni, Creator Spiritus (available here in Latin with English translation). See this link from EWTN for an outline of the general conditions for obtaining plenary indulgences.

VENI, Creator Spiritus,

mentes tuorum visita,

imple superna gratia

quae tu creasti pectora.

Qui diceris Paraclitus,

altissimi donum Dei,

fons vivus, ignis, caritas,

et spiritalis unctio.

Tu, septiformis munere,

digitus paternae dexterae,

Tu rite promissum Patris,

sermone ditans guttura.

Accende lumen sensibus:

infunde amorem cordibus:

infirma nostri corporis

virtute firmans perpeti.

Hostem repellas longius,

pacemque dones protinus:

ductore sic te praevio

vitemus omne noxium.

Per te sciamus da Patrem,

noscamus atque Filium;

Teque utriusque Spiritum

credamus omni tempore.

Deo Patri sit gloria,

et Filio, qui a mortuis

surrexit, ac Paraclito,

in saeculorum saecula.

Amen.