Following the Exodus from Egypt, Israel traversed the Sinai Desert for forty years. Ever since, we remember the miracales by dwelling in a sukkah, a hut of temporary construction with a roof covering of branches, for seven days and nights, we eat all our meals in the sukkah and otherwise regard it as our home.
Another Sukkot observance is the taking of the Four Kinds: a Lulav(palm frond), an etrog (citron), three hadassim (myrtle twigs) and two aravot (willow twigs). On each day of Sukkut (excepting Shabbat), we take the Four Kinds, recite a blessing over them, bring them together in our hands and wave them in all six directions. The Four Kinds represent the various types and personalities that comprise the Jewish community, whose intrinsic unity we emphasize on Sukkot.
The seventh day of Sukkot is called Hoshaana Rabbah ("Great Salvation") and closes the period of Judgment days that begun on Rosh Hashanah.