What is it?

Simchat Torah (meaning, “Celebration of the Torah”) is a one-day holiday that marks the completion of the annual cycle of the Torah reading. The final portion of Deuteronomy is read and then a new Torah reading cycle is immediately started with the Book of Genesis.
Many synagogues unroll the Torah scroll completely so everyone can see the whole Torah, from start to finish.

Dancing in the Streets

Simchat Torah begins in the evening, and involves raucous dancing, often mixed with lots of drinking, and singing with Torah scrolls. Children are paraded around on their parents' shoulders, and wave homemade flags. The idea here is to focus on how central the Torah is to Jewish life and the joy that the Torah can bring to the Jewish community.

Shemini Atzeret

In Israel and in some liberal communities outside Israel, Simchat Torah is celebrated together with another holiday--called Shemini Atzeret (meaning, “the eighth day of gathering”)--on the day that immediately follows Sukkot. In more traditional diaspora communities, Sukkot is followed by one day of Shemini Atzeret, which is then followed by Simchat Torah.