Shavuot (June 5-6, 2022), the holiday of “weeks”, commemorates Israel's receiving the Torah at Sinai. After the 49-day, 7-week countdown since Passover, we at last reach Shavuot on the 50th day. In the synagogue we read the story of the Revelation at Sinai, in which God descended upon Mount Sinai and communicated directly with Israel, giving the nation the Ten Commandments and its unique mission to God and mankind. We also read the Book of Ruth, telling the story of one of Israel's finest converts.
There are no specific mitzvot to fulfill on Shavuot, but some common customs are decorating the synagogue with plants (just as Mount Sinai blossomed), staying up all Shavuot night studying Torah, and eating dairy foods such as cheesecake.