“Rav Yossi said: It would have been appropriate had the Torah been given through Ezra, but Moshe preceded him… and even though the Torah was not given by him [Ezra], it was changed by him” (Sanhedrin 21b). The Talmud explains that this change relates to the “font” of the Torah, which was changed from ketav Ivri, the initial font in which the Torah was given, to ketav Ashurit, the “font” we have today in our Torah scrolls.
Our attitude towards Torah is a most fickle one. On the one hand, we demonstrated great faith in following Moshe into a barren desert; it's a story we recount as we plead for G-d's mercy on Rosh Hashanah. On the other hand, we complained at every turn in that same desert. We jumped at the opportunity to accept the Torah, instinctively declaring "Na'aseh v'nishma," yet 40 days later, we were dancing around a golden calf.
How should one celebrate the receiving of the Torah? The Talmud (Pesachim 68b) quotes a seemingly strange argument as to how to properly celebrate Yom Tov in general, and Shavuot in particular. "Rav Eliezer says, a person on Yom Tov either eats and drinks or sits and learns". One may choose how to celebrate, but that choice must be performed with full dedication. Apparently, he felt that trying to celebrate Yom Tov in two different ways gives neither its proper due.
"It was taught in the name of Rabbi Meir: Why was the Torah given to the Jewish people?" (Beitzah 25a). The simple answer—made famous by a Midrash that is taught at a very young age in all Jewish schools—is that we wanted to. "The Lord came from Sinai and rose from Seir unto them, He shined forth from Mount Paran (Devarim 33:2)...Rav Yochanan says: This teaches us that the Holy One, blessed be He, offered the Torah to every nation and every tongue, but none accepted it, until He came to Israel who received it" (Avodah Zara 2b).
The holiday of Shavuot is, outside of the observant Jewish community, a much-neglected holiday. It lasts only one day (two in the Diaspora), comes just as the summer is arriving and, unlike our other holidays, has no rituals associated with it--no shofar, matzah, or sukkah. The Torah itself makes no mention of any historical event associated with the holiday. Rather, it describes how, seven weeks after Pesach, "you may present a new grain as a meal offering to G-d" (Vayikra 23:15).