Summoning Greek Gods.
Prepare a fire.
Prepare a feast, with breads, fruit, meat and wine.
Find a white lamb (black for Hades), cut it down the belly.
Place the innards on the fire, giving prayer to you god.
Give gifts to the god, place next to fire, including lamb skin.
Eat your feast, giving portions to the god, by placing them in the fire, while praying.
You may be visited by your god. Beware that gods often take the guise of other mortals and animals.
If a guest arrives, provide them with food, drink and warmth. Do not turn them away, or hold them against their will. They may be gods, and guest hospitality is a sacred trait to Zeus.