Shabu'oth falls on the 6th of Siwan (and 7th for those who live outside the Land of Israel) every year. Yet it is the only holiday in the Torah whose date was not specifically mentioned. Rather, we are commanded to celebrate it 50 days after Pesah (Passover).
Concerning Shabu'oth It is not uncommon to hear someone ask: "Is the observance of Shabu'oth akin to the observance of a Yom Tob such as Rosh Hashanah, or is it of a lesser magnitude, similar to Purim?". It seems, to many, to be lacking many of the practices associated with other holidays. This is due to a lack of understanding of the importance and customs associated with the holiday.
Shabu'oth, which comes seven full weeks after Pesah (Passover), commemorates the receiving of the holy Torah at Mount Sinai. As such, it is one of the greater holidays in the Jewish calendar, whose observance is the same as Pesah, Sukkoth and Rosh Hashanah.
Click here for the Laws and Customs of Shabu'oth including links for dairy recipes and electronic greeting cards.
(Taken from the writings of Hakham Ya'aqob Menashe.)