"Tahajud" or "Salat-ul-Lail"
The Tahajjud prayer.
I think the prayer you are referring to is Tahajjud, which is a voluntary prayer said during the night, sometime after the obligatory Isha prayer.
Although Tahajjud is not one of the five daily prayers that all Muslims are required to say, it was regularly performed by the prophet Muhammad who also encouraged his followers to do the same.
The standard prayers that Muslims are obliged to observe are:
- Fajr (pre-dawn): This prayer is said before sunrise to begin the day by thinking of God.
- Dhuhr (noon): During the working day Muslim's should break and give some time to God.
- Asr (afternoon): Late in the afternoon when the working day is coming to an end and children are coming out of school it is important to break and give thanks to God.
- Maghrib (sunset): Muslims remember God again as the sun goes down and the day ends.
- Isha (evening): Before sleeping, Muslims take time to remember God and all he does for us.