Another classic chant is Veni Sancte Spiritu, or "Come, Holy Spirit."
You can hear both of them back-to-back below, in simple Gregorian chant.
Here is Maurice Duruflé's "Prelude, Adagio & Choral Varié" on Veni Creator Spiritus.
This Gregorian tune also inspired the German chorale, Komm, Gott Schöpfer. Here is a wonderfully simple arrangement for a small brass ensemble.
Here is an orchestral arrangement with the Berliner Philharmoniker.
Here is Bach's organ arrangement played on a beautiful Austrian instrument.
Veni Sancte Spiritus is the "Sequence" for Pentecost. It is a special liturgical text to highlight the festival day. It is usually sung before the Alleluias, which in turn precede the Gospel Reading. While the plainsong chant is simple, it seems Mozart had grander plans for the text.
With all that pomp, my favorite setting comes from the Taize Community. I have used this setting with as few as three parts and a solo. The verse here is sung in English, and is a good translation of the text. As Pentecost marks the nations hearing the disciples in their own languages, you will find other languages intertwined in this setting.