Based on the search results, it is not clear which Islamic holiday Muslims are celebrating today. However, there are two official Islamic holidays: Eid Al-Fitr and Eid Al-Adha. Eid Al-Fitr is celebrated at the end of the month of Ramadan, while Eid Al-Adha lands on the 10th day of Dhu al-Hijjah, the final month of the Islamic calendar. Other important Islamic dates include the Islamic New Year, Ashura, and the birthday of the Prophet Muhammad. It is worth noting that the dates of Islamic holidays vary each year on the solar calendar because Muslims use a lunar calendar.