Every seven years, following the Shmitah year, is the year of Hakhel. During the time of the Beis Hamikdash, on the second day of Succos, Motzaei Yom Tov Rishon shel Succos (right after the first day of Succos was over), the entire Jewish nation, anashim, nashim, vtaf (men, women, and children) gathered in the Beis Hamikdash for the mitzvah of Hakhel. The king was seated on a bimah shel eitz (wooden platform) in the azarah (courtyard)--the bimah was built immediately after Yom Tov especially for the occasion--and read selections from Sefer Devarim, called Mishneh Torah. According to many poskim even infants were brought to Hakhel. Geirim (converts) were also required to attend, even if they didnt understand what the king read. Everyone paid attention to his words, and envisioned that they were hearing the Torah Mipi haGevurah (straight from Hashem). May Hashem help us, that during this year of Hakhel, motzaei yom tov rishon shel Succos, we merit to actually fulfill the mitzvah of Hakhel in the third Beis Hamikdash.