Chanukkah.
Chanukkah commemorates the rededication of the Temple during the time of the Maccabees. The eight days represent the number of days that a single days' worth of oil lasted.
Purim.
Purim recognizes the events of Queen Esther against Haman, who tried to irradicate them. It is customary to cheer when her name or Mordecai is read during the reading of the Book of Esther.
Pesach.
Passover recollects the deliverance of Israel from the enslavement by Egypt. This festival observance unfolds throughout a formal meal. It was during this time; Yeshua was crucified for our sins reflecting the deliverance. Hence, HE is known as the Lamb of G-D.
Chag Ha Matzot.
The Feast of Unleavened Bread starts after Passover and lasts for seven days. The counting of the omer (one per day) to 50 starts the first day after the shabbat during this feast.
Yom Teruah.
Yom Teruah is the Feast of Trumpets. It has a Shofar Service that blows the Shofar with 99 sounds bursts. It begins the ten Days of Awe, which ends at Yom Kippur. These days are the days of introspection and repentance before G-D.
Tashlich.
Tashlich occurs in the morning following Yom Teruah. Within this service there is a casting of stones into the flowing water of the lake symbolizing of casting off sins.
Yom Kippur.
The Day of Atonement is the most somber Feast. It is a day of fasting from food from sundown to sundown. It is also customary to wear white this day. There are two services held this day, Shacharit (morning) in the morning and Minchah (gift) in the afternoon.
Sukkot.
Sukkot or the Feast of Tabernacles is the most festive festival. This does not only commemorate the living in booths (tabernacles), but also the birth of our Messiah, Yeshua (Jesus).
Shemini Atzeret.
Shemini Atzeret is the Eighth Day Assembly and is the last day of Sukkot. During this Festival is the prayer for rain. In Revelation, it is during this season that rain would be withheld for those who did not attend the feast during the Millenia Reign of the Messiah. This also would be the day Yeshua would be circumcised.