Lag B'Omer ("The 33rd Day of the Omer") happens on the 18th of Iyar. The origins of the holiday begin with the time of Rabbi Akiva. The Talmud (Yevamot 62:2) states that 24,000 of Rabbi Akiva's students died from a mysterious plague. The Talmud says that this was because they did not show proper respect to one another. We celebrate Lag B'Omer as the traditional day that this plague ended (Kitzur Shulchan Aruch, 120:1-10. Lag B'Omer is also the Yahrzeit, the anniversary of the death, of the Tanna Rabbi Shimon bar Yohai who authored the Zohar.

Lag B'Omer is a time of dancing and singing. Families go on picnics and outings. Children go out to the fields with their teachers with bows and rubber-tipped arrows. All of the rules of the Omer period are suspended on Lag B'Omer and it is a school holiday in Israel.

On the eve of Lag B'Omer huge bonfires are lit. This is to remind us that during that time there were rules set down by others which told the Jews that they could not mark the new month by lighting bonfires and could not worship HaShem. Shimon Bar Kochba led this revolt against tyranny and the bonfire lighting was reinstituted.