For those with Jewish friends, today is also Shushan Purim, a holiday I had not known of until this morning. Purim I knew of, martial holiday that it is, but it turns out that there is a special variation of the date of Purim that really appeals to me:
Purim is celebrated on the Adar 14 because the Jews in unwalled cities fought their enemies on Adar 13 and rested the following day. However, in Shushan, the capital city of the Persian Empire, the Jews were involved in defeating their enemies on Adar 13–14 and rested on the 15th (Esther 9:20–22). In commemoration of this, it was decided that while the victory would be celebrated universally on Adar 14, for Jews living in Shushan, the holiday would be held on Adar 15. Later, in deference to Jerusalem, the Sages determined that Purim would be celebrated on Adar 15 in all cities which had been enclosed by a wall at the time of Joshua's conquest of the Land of Israel.