Ostara is celebrated on the Spring Equinox (March 20 or 21st). It is the time of renewal and rebirth.
The Goddess Eostre is said to have found a wounded bird. To save its life she changed it into a rabbit. But the transformation was not complete so the rabbit retained the ability to lay eggs. how they got colored I do not know.
This is why we have Easter Bunnies and colored eggs.
Bunnies, of course, are a symbol of fertility. The term March Madness comes from the fact that in spring female rabbits are extremely fecund, often able to be impregnated again while still carrying their first litter. The madness part comes from the male rabbits who go crazy when they cannot mate with a desired female (typical : )
The egg is a symbol of rebirth.
In ancient Nineveh the Goddess Astarte (other names: Semiramis or Ishtar pronounced "easter") is said to have descended to earth near the Euphrates river in a giant moon egg.
As the story goes, Astarte's lover Nimrod was murdered, his body cut into pieces, and scattered to the four corners of the world. Unfortunately, she failed to resurrect him because she could not find his penis. Finally, she is said to have given birth to him.
And the Egyptian God Osiris too was resurrected by his Goddess, Isis, who like Astarte, had trouble locating Osiris' penis. Fortunately, she was able to solve the problem by creating a phallus of gold.
Another example of the Goddesses power over rebirth and death is Attis the consort of the Roman Goddess Cybele, who is resurrected on the Spring Equinox.
Also, the Roman God Mithras, born on the Winter Solstice (Yule) died and was resurrected on the Spring Equinox
Finally, Jesus the Christ continues the tradition by being reborn on Easter in the Christian faith.
We celebrate Ostara simply by gathering outdoors or simply by attending to the new season by gardening, planting herbs, or just spending time in nature. And, of course, Ostara Eggs
A simple Ostara spell can be performed with an Ostara Egg. At the exact time of the Equinox balance the egg on it's end. Do this simply by willing it to happen and focusing on the egg as you delicately find its balance. If it doesn't work try another egg. Some eggs are just off balance and will never stand up straight. The same is sometimes true of people, as well.
This picture is an actual egg I balanced easily. Make sure the surface is still and flat. The egg shouldn't roll when on its side.