Lag BaOmer was completely off our radar when we lived in the United States. We never had any real exposure to it until we made Aliyah, and now its approach is easily recognizable by kids walking down the street, schlepping huge pieces of wood, old furniture, sticks, and anything else that burns.
Lag BaOmer is a break, a time out, a moment to recall an ancient plague that may or may not have occurred, and perhaps a moment for reflection.
The Hebrew letter equivalent of 33 is pronounced Lag (lamed gimel), giving rise to the name Lag BaOmer for this particular day. There is no one particular reason that this day stands out from the other 48 days counted between Pesach and Shavuot, yet many fascinating traditions surround the special nature of this day.
An omer is a measure of grain, in this case, barley. In the days of Temple worship, we were to bring the first sheaf of barley to the Temple, followed by other items, as a sacrifice (Leviticus 9–14).
Driving across the Jezreel Valley these days, you can't miss the biblical echoes of the landscape. On Pesach we are to eat only cereal products made from the last year's harvest, baked with no leavening – and at the same time we are to clean out completely any remnants of any grain products from the old supply.
Judaism is filled with ritualized counting. From the seven ordered days of creation, to the repetition of forty throughout the Tanach (Hebrew Bible), to God's exhortation to Abraham to "count the stars, if you can count them…" Currently, we are in the midst of counting the Omer, the days from Passover to Shavuot.