Easter is a complex religious festival that is core to the message and hope of Christianity, has links to aspects of Judaism, and with regards to some its modern customs, draws on elements of ancient Germanic mythology and folklore. Here are three things you may or may not know about Easter.
The quartodeciman controversy: Easter is a moveable feast, the date of which is calculated based the precepts of a lunisolar calendar, one which takes account of both the solar year and the phases of the moon. The word quartodeciman (Latin for fourteen) refers to the fact that many early Christians linked Easter to the Jewish Passover and Feast of Unleavened Bread, which begin on the 15th of Nisan. But as the Jewish day begins at sunset of the previous evening, the Last Supper would have taken place on the evening of the 14th. Some early Christians, primarily those who were converts from Judaism wanted to link the date of Easter to Passover, but others who wanted to make Christianity more distinct from Judaism, and therefore more appealing to gentiles, argued that the observance of the Resurrection of Jesus should coincide with the Lord's Day (Sunday). At the Council of Nicaea in 325, the Church decided that Easter would be observed on the Sunday following the 14th of Nisan. However, for those interested in practicing Christianity as it was in earliest times, given that today (March 28, 2013) coincides with the 17th of Nisan, today would be actually be Easter.
The Easter bunny: The association of rabbits with Easter actually comes from the ancient belief that lagomorphs (rabbits, hares, and so on) were hermaphroditic. In other words, they were capable of producing offspring without sexual interaction - in essence, virgin birth. Hence rabbits became a symbol for Mary, the mother of Jesus, who theologically needed to be a virgin in order for Jesus to be conceived of the Holy Spirit. Rabbits are also associated with spring and fertility, as in "breeding like rabbits." In fact, hares are capable of superfetation - becoming pregnant with their next litter before they have given birth to the one they are presently carrying. The idea that Easter bunnies lay eggs appears to have its origins in German mythology, being mentioned in Grimm's fairy tales, and coming to America with the Pennsylvania Dutch (not really Dutch, but German).
The triple kiss: One of the key features of Easter celebrations in all Christian churches is the Paschal greeting, which takes the form of a versical, "Christ is Risen," and response, "Truly, He is Risen," or words similar to that. In Russia, it is common for parishioners to share a triple kiss - right cheek, left cheek, right cheek - known as the khristosovanie, or greeting (kiss) of Christ.The number three, of course, represents the Holy Trinity - Father, Son and Holy Spirit - the Three in One.
And, just because we can't get enough of this stuff, here's one more. Did you know that Easter eggs actually represent the empty tomb that the women discovered when they came to anoint the corpse of Jesus with spices in preparation for burial? Eggs look like stones, and when they break open they release a living being, just as the tomb of Jesus was opened to release the living Son of God. All you are left with is an empty broken shell. They were originally painted, or stained, red to represent the blood sacrifice of Jesus. Now, they are more brightly and intricately decorated to reflect the joy and hope of the risen Jesus.