This is from my old blog, The Geekie Hellenist.
This is my ritual for Diasia. This one had information that was very easy to be found, hence why I like the internet. Here is my Diasia ritual, to honor Zeus as Zeus-Hades. In this aspect, I don’t partake in Libations but dispose of it on the ground.
1) Purify the Altar area.
2) Take the barley and say, “As it was done in ancient times. I purify and cleanse this altar with this barley. With this barley I purify this altar and space so that I may give offerings, libations, and speak with glory and respect the gods of Mt. Olympus.”
3) Light a candle and say a hymn to Hestia.
Hestia, you who guard the sacred shrine of the Lord Apollon. The far-darter at goodly Pathos. With soft oil dripping ever from your locks. Come now to this house, come having one mind with Zeus the all wise-draw near, and with all bestow favor upon my song.”
Prayer to Hestia
Hestia, gracious goddess who sits at the heart of each home, who lives in the heart of each one who reveres you, each one who holds you dear, each one who turns to you for strength and harmony.
Hestia, goddess most needful, goddess most serene, goddess most esteemed, the heart of the city is yours as well, great goddess; within your realm are those who serve the state, who work for all the good of all–your blessings fall on the honest, goddess, your wrath on the corrupt, on those who betray their trust for gain. Defender of the householder, guardian of the hearthfire, Hestia, I praise and honor you.
4) Tell Zeus, in the form of Zeus-Hades, that your here. Say, “Zeus-Hades, here me.” You will use his title ‘Meilichios’ for this one but add this as well. The “Easy-to-be-entreated”, the gracious, accessible one, he who rages eager, panting and thirsting for blood.
5) There’s no invocation done.
6) There is no hymns for Zeus in this form.
7) This one you can do your own prayer
8) Offer incense to Zeus-Hades, saying, “Zeus-Hades, I offer this incense to you.”
9) Pour Libation onto the ground, saying, “Zeus-Hades, I offer this libation to you.”
10) Offer food, saying, “Zeus-Hades, I offer this sacrifice to you.”
Note: Do not eat any food or drink any of the libations. Zeus is a underworld deity in this ritual.
11) End the ritual by saying, “Hestia, goddess of home and hearth, to you I offer last of all as a pious mortal should. Tend to those whom I love and guard the houses of the pious. As the gods will it, so it shall be.”
It is so!