Lailat al Miraj is a special event for all Muslim community. Many Muslims celebrate this night and some Muslim do not celebrate the night. Because according to the Hadith or Quran, it is not recommended to celebrated. Even the date is not specific of Lailat al Miraj. In many Muslim countries, Lailat al Miraj is a Muslims holiday. The Lailat al Miraj is also called Night of Journey. In this day, Prophet Muhammad Sallallahu Alaihi Wasallam went to meet with Allah on the Arosh by physically and mentally. This journey is called Miraj. By this Journey, Allah gave 5 times prayer for all Muslim Ummah. If anyone performs 5 times prayer daily on time, then he will get the reward of 50 times prayer. If anyone does not perform 5 times prayer regularly, then he will get punishment. 5 times prayer is very important thing for Muslims.
“Exalted is He who took His Servant by night from al-Masjid al-Haram to al-Masjid al-Aqsa, whose surroundings We have blessed, to show him of Our signs. Indeed, He is the Hearing, the Seeing.” — Quran, Chapter 17 (Al-Isra)
Lailat al Miraj is followed by Islamic calendar but the date is unknown. This is why, the day is not celebrated. But some Islamic scholar guessed the date of Lailat al Miraj and they make it ritual to celebrate. For the same reason, the date is not celebrated.