Shavuot is known as Chag Habikkurim, the holiday of the first fruits. When farmers would notice that the first fruits had begun to ripen, they would bundle them together, fill their baskets and join the joyous procession to the Holy Temple to give thanks to God.
After the Romans destroyed the Temple in the first century, it seemed as if Shavuot and much of how Judaism was practiced would cease to exist. Without the Temple, Jews no longer had a place to make sacrifices and priests lost their central role. And so, in their wisdom, the rabbis transformed many of the rituals and holidays associated with the Temple.
The rabbis came to emphasize the connection between this holiday of Shavuot and the giving of the Torah. Counting seven weeks from the second night of Passover (Shavuot means weeks in Hebrew), Shavuot falls on the sixth day of Sivan. The Bible tells us that the Israelites received the Torah in the third month (the month of Sivan). Therefore, according to the rabbis, the sixth of Sivan is the anniversary of the giving of the Torah. On Pesach, we left the slavery of Egypt. On Shavuot, we received the Torah, the gift of God's commandments.
Today, Shavuot is celebrated as the anniversary of receiving the Ten Commandments. It is also the holiday on which Reform Jews celebrate confirmation, the ceremony in which 10th-graders affirm their acceptance of Torah and a commitment to Judaism.
Introducing young children to Hebrew and Torah on Shavuot is another beautiful custom of the holiday. In some traditions, a little honey is spread over the Hebrew letters on a page. As the child licks the page, she/he begins to realize that learning is a sweet experience.
Dairy meals are often served on Shavuot, relating to the following verse from Song of Songs: "Honey and Milk Are Under Your Tongue." This passage refers to the sweetness of Torah. (Others suggest that once the Israelites received the Torah, they had to adopt a kosher lifestyle. Eating only dairy was an initial simple solution.)
Lastly, it is customary to decorate the synagogue and home with greens and flowers, again reminding us of Shavuot as the time of the spring harvest.