Tomorrow night is Sukkot, which I used to observe as a child but don't now. Sukkot is described in the Bible as the "Feast of Tabernacles" in many translations, though it has nothing to do with the Tabernacle.

..."On the fifteenth day of this seventh month is the Festival of Sukkot, seven days for HaShem. [Leviticus 23:34].

The 15th day of a Jewish month is the "full moon" since all months start with the "new moon". Starting on the full moon makes sense since the holiday is also called "Festival of Ingathering" - think of "Shine on Harvest Moon". Sukkot is also called the "Season of our Rejoicing" since many consider it the most joyous Jewish holiday.

Outside of Israel observant Jews treat the 1st 2 of the 7 days as holy days - no work, etc. In Israel only the 1st day is observed in this way.

Sukkot means "booth" or temporary shelters. You assemble the shelter or "Sukkah" yourselves. It must have all least 3 walls and the roof must be made of cut materials that grew from the ground [branches, bamboo, etc.] Kids take part in decorating the Sukkah with colorful natural items.

During the holiday you are to spend as much time outside as you can in a booth. Many just have their meals there.

Prayer services include the use of palms and a lemon-like item called an "Etrog". Some scholars of the new testiment believe Jesus' procession with the palms occured during Sukkot and not the week before Easter, since this is when traditionally the Jews parade around with palms.

Most US Jews whom I know don't observe the holiday.