At some synagogues, like Yorktown Jewish Center where I belong, when a 13-year-old becomes a bar (male) or bat (female) mitzvah – which is to say, reaches adulthood in the faith (spiritually speaking) -- among the tokens of congratulation conferred on the overnight grown-up is The Jewish Book of Why, accompanied by its companion, The Second Jewish Book of Why.
The “Why” can be historically answered, as in, “During this three-week period in 586 B.C. … the walls of Jerusalem were breached [and it is] observed as a period of mourning.” What’s the question? Oh, right, this isn’t Jeapordy, but in any case it is, “Why are weddings not permitted during a three-week period each summer?” (Funny, the catering halls aren’t aware of that, are they?).