Christians celebrate this resurrection on easter day or Easter Sunday. Easter also refers to the season of the church year called Eastertide or Easter year.Easter is a moveable feast, which means that it does not occur on the same date every year. Easter Sunday dates changing every year. For example, in the year 2010, Easter Sunday date fell on 4th April but Easter Sunday 2011 will fall on 24th of April. The easter sunday datevaries because it is determined using a calculated lunar calendar. It\'s the First Sunday, after the First full moon, after the 21st March. Easter is celebrated in both religious and secular ways by many christian families throughout the world.The first week of the Easter Season is known as Easter Week or the Octave of Easter. Easter also marks the end of Lent, a season of fasting, prayer, and penance.