Two major Muslim holidays are celebrated around the world: Ramadan, the month of fasting, and Hajj, the month designated for pilgrimage to Mecca for Muslims who can afford it. Several other holidays are celebrated by most Muslims, including Eid Al-Fitr, which falls at the end of Ramadan, and Eid Al-Adha, which occurs at the end of Hajj.
Muslim holidays are calculated according to the Muslim calendar, which differs from the Gregorian calendar used around the world. To add complications to the matter, Sunni and Shi'a Muslims calculate their calendars differently, so disputes have been known to occur in regards to when a holiday should actually be celebrated. In communities with a large Muslim population, Muslim holidays are often designated as general holidays, with the most dominant sect's calendar being used to determine when these holidays should occur.
The first holiday of the year is Islamic New Year, which falls on the first day of the first month. 10 days later, devout Muslims observe Ashura, a day of fasting and contemplation which is set aside to think about faith, life, and other issues. Many Muslims also celebrate Mawlid An-Nabi, the birth of the Prophet Muhammad.
Ramadan falls during the 10th month of the Islamic calendar. During Ramadan, Muslims fast during the daylight hours, and often attend additional religious services. At the end of Ramadan, Muslims hold Eid Al-Fitr, the fast-breaking holiday, which is treated as a great excuse to hold big parties with lots of food, dancing, and general celebration to commemorate the end of the fasting. Some mosques also hold open mosque days around this time, to encourage curious potential converts to explore Islam during the Muslim holidays, when people are especially active.
After Hajj in the 12 month, Muslims all over celebrate Eid Al-Adha, the Day of Sacrifice, which commemorates the story of Abraham. It is traditional to slaughter a lamb or sheep on Eid Al-Adha, with people dividing the meat for themselves, family members, and the poor. People also hold parties and celebrate with meals on Eid Al-Adha.
Jumu'ah, known as Friday to English-speakers, is also a Muslim holiday. Fridays are set aside as Muslim holidays much like Saturdays in the Jewish faith and Sundays in the Christian faith. On Fridays, people attend services at the Mosque, and take time to pray and celebrate their faith. In Muslim areas of the world, Fridays are usually not treated as business days for this reason.