Ma'aser Behemah - tithing the animals. With joy. On the first of Tishrei, as interpreted from the biblical text. Which of course yields a dispute. And doesn't involve the facts on the ground, somehow. Though it does entail the cycle of time, and why it's important to mark the calendar. Also, a day of judgement in Tishrei! With a "covering" hiding the moon. Plus, the power of the process of Rosh Chodesh, and the human decree that defines Rosh Hashanah. Including judgement for the whole world (with Israel/Jews judged first).