Happy Sukkot To All My Jewish Readers...
Like Passover and Shavu'ot, Sukkot has a dual significance: historical and agricultural. The holiday commemorates the forty-year period during which the children of Israel were wandering in the desert, living in temporary shelters. Sukkot is also a harvest festival, and is sometimes referred to as Chag Ha-Asif, the Festival of Ingathering.
In honor of the holiday's historical significance, we are commanded to dwell in temporary shelters, as our ancestors did in the wilderness. The commandment to "dwell" in a sukkah can be fulfilled by simply eating all of one's meals there; however, if the weather, climate, and one's health permit, one should live in the sukkah as much as possible, including sleeping in it.
Many Americans, upon seeing a decorated sukkah for the first time, remark on how much the sukkah (and the holiday generally) reminds them of Thanksgiving. This is not entirely coincidental. Our American pilgrims, who originated the Thanksgiving holiday, were deeply religious people. When they were trying to find a way to express their thanks for their survival and for the harvest, they looked to the Bible for an appropriate way of celebrating and based their holiday in part on Sukkot.