The Omer itself, the seven weeks between Passover and Shavuot, is traditionally a time of mourning and introspection, but the 33rd day of the Omer (33 is lamed-gimel to numerologists, two letters which can be enunciated together as "lag"), is a time for fiery revelry.
The official, on-the-parchment raison d'etre for Lag Ba'Omer is the cessation of a plague afflicting the students of Rabbi Akiva, a major sage living in post-Temple Roman Judea. Supposedly, the plague, inflicted by God because the students had not been displaying appropriate levels of scholarly camaraderie, had killed 24,000 during the Omer; when it came to a sudden stop on Lag Ba'Omer, only five remained, including heavy hitter Shimon Bar-Yochai, purported author of the Zohar, the foundation text of Kabbalah (Lag BaOmer is also traditionally considered Bar-Yochai's yahrtzeit, the anniversary of his death).
However, both scholars and laymen over the years have wondered if the Talmud, in chalking up the deaths of Akiva's students to plague, was not dealing in a bit of not-uncharacteristic euphemism. In addition to his scholarship, Akiva was known for his revolutionary sympathies; the rabbi was a firm supporter of Bar-Kokhba, the Jewish revolutionary who mounted a bloody, intermittently successful revolt against Roman rule in the second century CE (in fact, it was Akiva, who thought Bar-Kokhba may well have been the Messiah, who gave him his nickname, a Messianic reference meaning "son of a star" in Aramaic). In this interpretation, "students" is code for "soldiers," and on Lag Ba'Omer, months of heavy losses for the Judean rebels were turned around when they annihilated a Roman cohort or two.
Will we ever know the truth? Probably not, but in the interim, we could always hedge our bets by lighting bonfires.
Oh yes, the bonfires. You will notice those. Poor Gan Sacher, barely recovered from the grill-fest of Independence Day, becomes pyromania central as scads of the faithful and youthful put flame to uncomfortably large piles of logs. Officially, this is in honor of Shimon Bar-Yochai lighting up the world with his Kabbalistic scholarship; one suspects, however, that many of the suspiciously secular-seeming teenagers dancing about the flames (Lag Ba'Omer is a day off school) wouldn't know what to do with page one of the Zohar's dense mysticism and idiosyncratic Aramaic. Any excuse for a bonfire, however.
As it's a day off, there are no shortage of parties at nightlife venues around the city. Weddings are also a popular diversion, as the temporary cessation of the Omer period's mourning rituals mean it's once again kosher to tie the knot. The more religious celebrations of Lag Ba'Omer, which include first haircuts for three-year old Jewish boys and plenty of ecstatic dancing, are centered far from Jerusalem at Mount Meron, near Safed in the Galilee, so in Jerusalem, you're far more likely to see kids burning pilfered shipping pallets than jubilant scholars. But that's fun too.
Just don't forget to close your windows before going to sleep. That soot'll get all over everything.
