Purim

Culture/religion: Judaism
Date: March 17
Purim is a Jewish festival celebrated every year on the 14th of the Hebrew month of Adar. The celebration commemorates the salvation of the Jewish people in the ancient Persian empire from Haman’s plot “to destroy, kill and annihilate all the Jews, young and old, infants and women, in a single day,” as told in the Megillah (book of Esther). It’s also a celebration of God’s intimate involvement in every aspect of this world.
Observances on Purim include: Reading the Megillah (book of Esther), which recounts the story of Purim; giving money to at least two poor people; sending gifts of food to at least one person and a festive feast. It is also customary for children to dress up in costumes.
Purim begins at sundown March 16. Work should be avoided.
Pronunciation: PAWR-im / poo-REEM / PUH-rim / PEE-rim
Greetings: “Happy Purim;” in Hebrew – “chag Purim samayach” (pronounced KHAG poo-REEM sah-MAY-ach)
Sources:
What is Purim?, Chabad.org
Glossary of Jewish Terminology, Judaism 101, jewfaq.org
Holi

Culture/religion: Hindu
Date: March 18
Holi, sometimes called “the festival of love” or “the festival of colors,” is one of the most revered and celebrated festivals in India. This is a day when people come together to forget all resentments and bad feelings toward others.
The ritual of Holi begins by lighting a bonfire on the day prior to Holi; a process symbolizing the triumph of good over bad. The main day of Holi celebrations, Dhuleti, people throw brightly colored powder on each other or spray each other with brightly colored water, adding the positivity of color to the celebration.
Sources:
Ostara

Culture/religion: Pagan/Wiccan
Date: March 20
“Ostara” is just one of the names used for the spring equinox celebrated in many different cultures and a variety of ways around the world. For early Pagans in the Germanic countries, this was a time to celebrate planting and the new crop season.
Ostara (Eostre or Eastre) is the Germanic goddess of spring and dawn who was traditionally honored in the month of April with festivals to celebrate fertility, renewal and rebirth.
Sources:
Who is Ostara?, NorthernPaganism.org
Ostara, The Goddess and the Green Man
History of Ostara, The Spring Equinox, Learn Religions
March month-long observances
Irish American Heritage Month
National Developmental Disabilities Awareness Month
Women’s History Month