A. This period known as the “Omer” is Biblically the countdown to the eagerly anticipated Revelation at Sinai. That’s joyous. But later, in the times of the Mishna, 24,000 students died in a mysterious plague, during an already difficult time for the Jewish people, under Roman persecution. In semi-mourning for this national tragedy, and symbolically other historic national tragedies as well, no weddings take place during this period, and we don’t listen to live music. Some won’t even listen to tapes or CDs, unless it is educational, and not entertainment. There is also some discussion as to when this period begins and ends, and the various opinions allow room for stringency and leniency in this observance.