Today is Tisha B'Av ("the ninth of Av"). This fast day in Judaism commemorates the destruction of the first and second temples in Jerusalem (586 BCE and 70 CE). The day also commemorates other tragedies that have happened to the Jewish people, like the expulsions of Jews from England in the 13th century and from Spain in the 15th century.
As the Judaism 101 site indicates, "The restrictions on Tisha B'Av are similar to those on Yom Kippur: to refrain from eating and drinking (even water); washing, bathing, shaving or wearing cosmetics; wearing leather shoes; engaging in sexual relations; and studying Torah. Work in the ordinary sense of the word [rather than the Shabbat sense] is also restricted. People who are ill need not fast on this day. Many of the traditional mourning practices are observed: people refrain from smiles, laughter and idle conversation, and sit on low stools. In synagogue, the book of Lamentations is read and mourning prayers are recited. The ark (cabinet where the Torah is kept) is draped in black."