Buddhism has no "holy day" during the week like the Christian's Sunday
There are many special or holy days held throughout the year by the Buddhist community. Many celebrate the birthdays of Bodhisattvas in the Mahayanatradition or other significant dates in the Buddhist calendar.
Important festivals and celebrations:
Buddhist New Year
In Theravadin countries, Thailand, Burma, Sri Lanka, Cambodia and Laos, the new year is celebrated for three days from the first full moon day in April.
In Mahayana countries the new year starts on the first full moon day in January.
Some Buddhists have other traditions: Chinese, Koreans and Vietnamese celebrate late January or early February; Tibetans usually celebrate about one month later.
Vesak ("Buddha Day")
Buddha's Birthday is known as Vesak or Visakah Puja (Buddha's Birthday Celebrations). Vesak is the major Buddhist festival of the year as it celebrates the birth, enlightenment and death of the Buddha on the one day, the first full moon day in May.
Magha Puja Day (Fourfold Assembly or "Sangha Day")
Magha Puja Day takes places on the full moon day of the third lunar month (March). It celebrates an ordination of many follows of the Buddha by the Buddha at the Veruvana Monastery.
Asalha Puja Day ("Dharma Day")
Asalha Puja ( pay homage to the Buddha) on the full moon day of the 8th lunar month (approximately July). It remembers the Buddha's first teaching: the turning of the wheel of the Dhamma (Dhammacakkappavattana Sutta) to the five ascetics at the Deer Park (Sarnath) near Benares city, India.
Uposatha (Observance Day)
The four monthly holy days observed in Theravada countries
Pavarana Day
This day marks the conclusion of the Rains retreat (vassa). In the following month, the kathina ceremony is held, during which the laity gather to make formal offerings of robe cloth and other requisites to the Sangha.
Kathina Ceremony (Robe offering ceremony)
Held within one month of the conclusion of the Vassa Retreat. New robes and other gifts may be offered by the laity to the monks.
Anapanasati Day
The Buddha presented his instructions on mindfulness of breathing (anapanasati).
Abhidhamma Day
In the Burma this day celebrates marks Buddha's visit to the Tushita Heaven to teach his mother the Abhidhamma.
Loy Krathong (Festival of Floating Bowls)
At the end of the Kathin Festival season, in Thailand on the full moon night of the Twelfth Lunar month people bring bowls containing flowers, candles and incense sticks, and float them in the water.
The Ploughing Festival
In May, when the moon is half-full, Buddhists celebrate the Buddha's first moment of enlightenment, which is said to have happened when the Buddha was seven years old, when he had gone with his father to watched the ploughing.
The Elephant Festival
The Buddha used the example of a wild elephant which, when it is caught, is harnessed to a tame one to train. In the same way, he said, a person new to Buddhism should have a special friendship of an older Buddhist.
The Festival of the Tooth
The Buddhas tooth is kept as a relic. Once a year in August, on the night of the full moon, there is a special procession for it.
Ulambana (Ancestor Day)
In the Mahayana tradition from the first to the fifteenth days of the eighth lunar month. Buddhists remember their ancestors.
Avalokitesvara's Birthday (Kuan Yin)
A festival which celebrates the Bodhisattva ideal represented by Avalokitesvara (the Buddha of compassion). It occurs on the full moon day in March.
Bodhi Day (Enlightenment Day)
Bodhi Day honours the enlightenment of Siddhartha Gautama -- the Buddha on the eighth of December. The day is observed with prayer, meditation and teachings.