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).
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.
What makes this holiday a favorite among secular Israelis, while it is almost forgotten by Jewish kids in the Diaspora?
I had always thought of Jewish cemeteries as solemn places – but that was before going to a hilloula (festivity) 30 years ago in the Moroccan town of Ouazzane on Lag BaOmer, the Jewish holiday that falls on the 33rd day between Pesach and Shavuot.