Ostara, Eostre, or Spring Equinox falls between March 19 to 23 (the date varies every year for each equinox) where we begin celebrating the first signs of Spring. A time to bless the seeds and seedlings that will be planted when the ground thaws. Day and night are equal on this day, hence the name Equinox.
For Wiccans and Witches, Ostara is a fertility festival celebrating the birth of Spring and the reawakening of life from the Earth. This is another Pagan holiday adapted by the Christian Church to convert Pagans to Christianity. You will find the same symbolism and practices among Wiccans and Pagans that happen in Churches only the deity names are different. I will not go into detail about what Christians do on their holy day as we have some wonderful Christian writers here at BellaOnline.com and I value their opinions on their holy days.
Wiccans celebrate Ostara in many ways and this one of the most sacred days for most Wiccans I know. Activities include lighting fires at sunrise (either in the fireplace/pit or candles on your altar), ringing bells, and decorating hard-boiled eggs which is an ancient Pagan custom associated with the Goddess of Fertility. There is much symbolism in eggs themselves. The golden orb of its yolk represents the Sun God, its white shell is seen seen as the White Goddess, and the whole is a symbol of rebirth.
In Greek mythology, spring marked Persephone's return from the underworld to reunite with her mother Demeter. Remember around Samhain, Persephone is kidnapped by Hades. Dememter and Hades stike a deal that Persephone goes to the Underworld for several months and in her mouring for her loss, Demeter makes the world cold and barren while she is gone. So in the spring, Demeter brings the Earth back to life due to the return of her daughter.
A simple houseblessing you can perform on Ostara Eve, light a purple candle and burn patchouli incense. Carry them both through the house and say:
"Farewell to wintry spirits and friends; On marrow we greet the spirits of spring. Our blessings to thee as your way you wend; and merry we'll meet next winter again." Blow out the candle and say: "Merry meet, merry part, and merry meet again."
Here is a great example of an Ostara ritual performed by a coven in New York to give you one idea of a ritual to perform:

