Eating matzah, sitting in a sukkah, hearing the shofar, EATING CHEESECAKE!
Have you ever thought about the fact that over Shavuot - the time when the Jewish people received the ‘Instruction manual for life’ - there are no intrinsic Jewish traditions? What I mean by intrinsic is that there are no unique Torah obligations like having matzah on Pesach or sitting in a sukkah on Sukkot.
All-night learning developed based on the fact that the Israelites slept all that night, until two hours into the day, since sleep at Shavuot-time is pleasant and the nights are short... God came and found them sleeping; He began to stir them with trumpets and Moshe had to wake them from their sleep for the great encounter with the King of Kings... (Shir HaShirim Rabbah 1:57, Pirkey DeRebbi Eliezer 40)
It is called Tikkun Leil Shavuot - fixing up the night of Shavuot, where we overslept.
There are several reasons (7 on Aish.com) for the Shavuot tradition of eating cheesecake, a yummy Jewish tradition, and here is one of them: The Torah is likened to milk, as the verse says, "Like honey and milk [the Torah] lies under your tongue" (Song of Songs 4:11). Just as milk has the ability to fully sustain the body of a human being (i.e. a nursing baby), so too the Torah provides all the “spiritual nourishment” necessary for the human soul.
And lastly floral displays in our Synagogues and homes. This custom of flowers and greens was based upon a statement in Midrash that the foot of Mount Sinai (where the Jews stood in awe, awaiting the granting of the Torah) was carpeted with greens and sweet-smelling flowers. So we do the same.
Shavuot is a time for Jews to show how much we value our Torah. The Jewish traditions that have developed over the centuries certainly demonstrate ‘The People of the Book’s love for The Book - the Torah.’