Speaking of the Holy Spirit

Orthodox frequently invoke the Holy Spirit when they pray or do things. One of the commonest prayers in Orthodoxy is the "O Heavenly King":

O Heavenly King, Comforter, Spirit of Truth, Who art everywhere present and fillest all things, treasury of good things and giver of life, come and abide in us and cleanse us of all impurity, and save our souls, O Good One.

For an interesting new discussion of Orthodoxy and Pentecostalism, go here (PDF).