In my family, and many others, I am sure, welcoming Elijah into the house on Passover also means offering him a glass of wine, which we always referred to as "Elijah's Cup." We fought over the honor of opening the door for him. Elijah's cup is always a fancy goblet, set in the middle of the table, filled to the brim with wine for him. Historically, there have been rabbinical disagreements over whether Jewish people are supposed to drink four or five glasses of wine during the Passover meal, the Seder, and this fifth glass has turned into Elijah's cup, a fifth cup, a way of hedging on what the requirement really is supposed to be. When I was a very young child, maybe four or five, on one Passover at an aunt and uncle's house, I swear I saw the level of wine go down in Elijah's cup after the door was opened. My family has always been quite skeptical about this. Of course, imagine the effect of even a few sips of wine on a small child!