The festival of Shavuot is a celebration of the day that God spoke to the people Israel and gave them His Holy Commands. He spoke, not just through His prophet Moses; but to every man, woman and child of the nation of Israel.
This is a "milk festival" meaning that, in Jewish tradition, milk products are served to the exclusion of meat. Since dairy products are more common in desserts than meat products, this tends to be a very sweet celebration.
We fill the evening with goodies and games. We traditionally read the story of Ruth. This story is particularly important to us as gentiles because Ruth is a Moabitess included into the people of Israel, destined to be the matriarch of King David and our promised Messiah Yeshua.