In the Quran, there are four holy months:
It is been said that the four sacred months are; Muharram, Rajab, Dhul Qida and Dhul Hijja. However, we dissagree with that(see calender.) We say the four sacred months are; Dhul Hijja, Muharram, Safar, and Rabi` I.
Also, Ramadan, the Month of Fasting, is also a holy month. Anyways, the following are the Islamic Holidays;
New Year(Muharram 1st.)
Holidays! Who doesn't love holidays? They are the only times you are allowed to go wild. Even closed society in the Muslim World, people have more freedom during the holidays. Even during the time of the Jahiliyyah(Ignorance) the `Arabs were flexible during the holidays.
Surely the number of months with God are twelve months in God's ordinance since the day when He created the heavens and the earth, of these four being sacred; that is the right reckoning; therefore be not unjust to yourselves regarding them, and fight the polytheists all together as they fight you all together; and know that God is with those who guard (against evil). Surrat ul Tawbah, 9.36
`Eid ul Fitr/Festival of Breaking the Fast(Shawwal 1st)
`Eid ul Adha/Festival of Sacrifice(Dhul Hijja 10th)