Religious holidays run according to the Muslim lunar calendar. Because it is 11days shorter than the Gregorian calendar, holidays move forward 11 days each year, and exact days should be checked with the tourist office.
The most important Muslim festival is the month of daylight fasting, Ramadan(in the year 2006 it begins on 23 September). At sunset(Eid al-Fitr) the fast is broken and communal meals are taken.
It's every Muslim's duty, if possible, to perform a pilgrimage to Mecca during their lifetime. Traditionally pilgrims set out in April/May(Eid al-Adhah), and this period sees streets festooned with coloured lights and banners and Egyptians wearing their finery.
Other important religious festivals include the prophet Mohammed's birthday(mid-summer) and the Islamic New Year(April).