From The Writer’s Almanac from American Public Media:

Today is Easter Sunday in the Christian Church, the holiday that celebrates Jesus’ resurrection from the dead. Easter is one of the few floating holidays in the calendar year, because it’s based on the cycles of the moon. Jesus was said to have risen from the dead on the first Sunday after the first full moon of spring. For that reason, Easter can fall as early as March 22nd and as late as April 25th.

The word “Easter” comes from an ancient pagan goddess worshipped by Anglo Saxons named Eostre. According to legend, Eostre once saved a bird whose wings had frozen during the winter by turning it into a rabbit. Because the rabbit had once been a bird, it could still lay eggs, and that rabbit became our Easter Bunny. [mjh: another pagan belief co-opted by those seeking power for themselves.]