SG this is for you! =)

In the Torah (the first five books of Moses), there were seven sacred festivals instituted by God:
The Feast of Passover (Pesach) - celebrated the night when the angel passed over the Hebrew households in Egypt.
The Feast of Unleavened Bread - commemorated the first 7 days of the Exodus when the Hebrews left Egypt in such a hurry that they did not have time to add yeast to their dough.
The Feast of Weeks - also called the Pentecost (Shavuot). It marked the end of the harvest and offering of first fruits.
The Feast of Trumpets (Yom Teruah) - the blowing of a ram's horn, or shofar, to call the people to prepare for the Day of Atonement (Yom Kippur). Later this day became the Jewish New Year (Rosh Hashanah).
The Day of Atonement (Yom Kippur) - the most solemn day of the year. On this day, the High Priest sacrificed sin offerings to atone all the sins of the people and entered the Most Holy Place to offer incense.
The Feast of Tabernacles (Sukkot) - celebrated the completion of the great fall harvest and remembered the Hebrews in the Exodus living in tents for 40 years.
The Feast of the Last Great Day (Shmini Atzeret) - marked the conclusion of the festival year.

Of the above, 3 were considered as "major feasts": the Feast of Passover (Pesach), the Feast of Weeks (Pentecost), and the Feast of Tabernacles (Sukkot). These are often called "pilgrim feasts" because all adult males were required to travel to the sanctuary to take part (Deuteronomy 16:16).