Islam:
Al-Hijra — Islamic New Year. Marks the end of Mohammad's journey from Mecca to Medina.
Eid ul-Adha — Festival of Sacrifice. This is a four day holiday marking the sacrifice of Abraham.  It also highlights the end of the annual pilgrimage to Mecca, called Hajj.  Prayer are held at the mosque followed by an evening feast.
Eid ul-Fitr  — End of Muslim Month of Fasting (Ramadan).  A celebratory meal on the evening of this day.  It is a three day celebration and many will attend early morning prayers, affecting attendance.
Prophet's Birthday -- Celebration of the birth of the Prophet Muhammad. Celebrations, communal meals and discussions on Islam usually take place on this day.
Ramadan — Muslim Month of Fasting. Muslims fast from sunrise to sunset with the last ten days reserved for possible all night prayer vigils. Attendance should not be affected.
Buddhism:
Chinese New Year--A three-day holiday in China and Hong Kong, the Chinese New Year is an important Chinese holiday that is celebrated in many areas with Chinese populations. While the regional customs and traditions vary across regions, it is traditional for the Chinese to give out gifts and clean and decorate their homes to sweep away ill-fortunes to welcome the incoming luck.
Nirvana Day--Celebrated by some Buddhist on February 28th. Nirvana Day is the celebration of Buddha's death when he reached total Nirvana, at the age of 80.
Losar--Tibbetan Buddhist New Year (Year 2139: the Water Dragon).
Songkran Festival--Celebrated in Thailand, Cambodia, Myanmar, Sri Lanka as the traditional New Year's Day
Wesak--Celebrated as one of the most important Buddhist festivals, Wesak celebrates the Buddha's birth, enlightenment, and death.
Wassana--Recognized as Buddha's first teaching, Wassana also marks the beginning of the 3-month 'Rains Retreat' for nuns and monks.
Obon--The summer Obon season perpetuates the Buddhist tradition of honoring family ancestors, who are said to return to the mortal world to visit.
Dhamma Day--This day commemorates the preaching of Dhammacakkappavattana Sutta which literally translated means "When the Wheel of Dharma is set to Motion". It is believed to be the day when Lord Buddha imparted his first teaching.
Confucius's Birthdday
Pavarana--This date marks the end of the intensive practice Buddha endured.
Kathina--Donations especially robes are given to monks to express gratitude.
Bodhi Day--According to traditions, Bodhi marks the day that Siddhartha Gautama became the historical Buddha by which he experienced his first enlighten
