There are two main holidays in Islam, Eid Al-Fitr and Eid Al-Adha. The way that holidays are recognized can vary across cultures, as well as across sects of Islam, Sunni and Shia. Muslim holidays generally follow the lunar calendar, and thus move each year relative to the solar calendar.The Islamic calendar has 12 months and 354-355 days. Sunni and Shia lunar calendars do not always coincide: sometimes a Shia holiday and the same Sunni holiday occur on two different days, typically two successive ones.
Islamic dates are based on a lunar calendar, and may vary by 1-2 days from what is predicted below .
Ashura is commemorated by Shi'a Muslims on the ninth and tenth days of Muharram on the Islamic Calendar. Ashura is an Arabic word meaning "ten", and according to Sunni schools of thought it is a day of optional fasting. Jews in the city of Madina fasted only one day, on Yom Kippur, the 10th of Tishrei; so the Prophet Muhammad would fast too, believing that Muslims are closer to Prophet Moses than the Jews themselves. According to Islamic tradition, Muhammad fasted along with the neighboring Jewish communities on this occasion, and according to narrations, Muhammad fasted on both the 9th and 10th of Muharram.
By Islamic tradition, this day commemorates God saving Moses and the Israelites from Pharaoh in Egypt as they crossed the Red Sea (the Exodus day). According to Judaism, the Israelites left Egypt on the first day of Passover, and they crossed the Sea of Reeds seven days later on the 21st of Nisan, both of which are celebrated as holidays with meals.
According to Shi'a tradition, 10 Muharram is also the day on which Muhammad's grandson, Husayn ibn Ali, was martyred in the Battle of Karbala. For Shi'a Muslims, this is a day of mourning.
Laylat al-Qadr is Arabic for “The Night of Power”. It falls on one of the last ten days of Ramadan on an odd numbered day. It is considered the holiest night of the year, since it is the night in which the Qur'an was first revealed. It is also considered better than a thousand months [Qur'an 97:1-3]. It is said that if a person performs voluntary worship on this night, that worship is equal to a thousand months or approximately 80 years.
Laylat ul Isra and Mi'raj is Arabic for the “Night of the Journey and Ascension”. It is on 27th of Rajab. It is the night when Muhammad was, according to Hadiths, taken to “the furthest mosque” (generally understood to be Jerusalem) on a Buraq (a beast resembling horse with wings; some people consider it a cherub) and ascended to the highest level of the heavens. It is said that he negotiated with God about the number of prayers, which started at fifty a day, but on his way down he met Moses, who asked him to ask for a reduction in the number because the requirement was difficult for Muhammad's people. Muhammad returned to God and several times asked for, and was granted a reduction of five prayers, until the number was reduced to five in total, with the blessing that if they were properly performed, the performers would be credited with fifty prayers instead of five. The event of this Night has also been described in Quran in Part 15 the beginning of Surah Isra.
Ramadan is the month in which Muslims must fast from sun-up to sun-down. This is meant to feel how the poor people are without food or water. In addition, Muslims close their bodies off from earthly demands by denying themselves food and drink. This in turn allows for the nourishment of the soul.
Fasting is more than just the mere denial of food and drink. Muslims must also abstain from smoking and sexual contact. In addition, there are culture-specific beliefs regarding the watching of television, listening to music, and the perusal of any secular vice that does not in some way enhance spirituality.