The Palmach division of the Haganah was established on Lag B’Omer 1941.
The Gadna program (youth brigade) was also established on Lag B’Omer 1941, and their symbol is the bow and arrow.
Ben-Gurion gave the order to officially create the IDF on Lag B’Omer 1948 (assuming he issued it after sunset on May 26, 1948).
Lag B’Omer is the official day for saluting IDF reserve soldiers.
Rabbi Menachem Mendel Schneerson ZT”L writes in his Likkutei Sichos that the reason why the day should be called Lag BaOmer and not Lag LaOmer is because the Hebrew words Lag BaOmer (ל״ג בעמר), spelled without the “vav”, have the same gematria as Moshe (משה), and Rabbi Shimon bar Yochai was mystically a spark of the soul of Moses.
Hundreds of thousands of Jews visit the tomb of Rabbi Shimon Bar Yochai, in Meron on Lag B’Omer.
Lag B’Omer has joined Rosh Hashana to become the only other 2 day holiday in Israel. In order to avoid possible desecration of Shabbat this year (2013), the Rabbanut asked that schools be closed on Sunday and Monday, and that bonfires be delayed until Sunday afternoon. Most people ignore the request to delay the bonfires.
Jerusalem pollution levels rise 6 times normal on Lag B’Omer due to the bonfires.
3600 tons of wood are burned.
Construction sites lose on average, NIS 15,000 worth of material, as children raid the sites for wood.
500 firetrucks and 300 firefighters are on duty in Israel.
Feel free to add your Lag B’Omer trivia in the comments.