Turn Up For What? The Omer.
It’s that time of year again, the 49-day period between the second day of Passover and the day before Shavuot known as Sefirat HaOmer, or counting the Omer, during which we well, count, as commanded. The traditional reason cited in the Talmud is that this is in memory of the 24,000 students of Rabbi Akiva who died in a plague for not honoring one another properly as befits Torah scholars.
It’s a weird, strange time, full of any number of semi-mourning practices (dependent on regional or familial custom), forbidding any combination of haircuts, shaving, listening to instrumental music, or conducting weddings, parties, and dinners with dancing. All such restrictions, however, are lifted on the 33rd day of counting, also known as Lag b’Omer, because it was on that day that the epidemic finally halted.