Baptist minister Mark Tronson, who has long been interested in Biblical Jewish interpretation, quotes from the Bridges for Peace Mission in Jerusalem, which explains some of the traditions.
The book of Esther, called "The Megillah" (to distinguish it from the other four 'megillahs', or 'scrolls' that are read at different times) is read aloud in the synagogues.
During the service, every time the name Haman is read, the entire congregation makes loud noises to drown out the sound of his name. They boo, hiss, and shake noise-makers called "rashanim." Every time the name Mordechai is read, they cheer loudly.
Many costume parties are held, with outlandish costumes being the norm. In Israel, children dress up in costumes not seen elsewhere, such as Torah scrolls (the 5 books of Moses, Genesis to Deuteronomy) and high priests. The fast of Esther, commemorating the three days of fasting and praying prior to Esther visiting the King to ask for her people to be saved from Haman's plot of massacre, is observed by many.
As well as celebrating and being commanded by the Talmud (the interpretations of customs set down my many generations of Rabbis) to 'eat, drink and be merry', Jewish people donate gifts (traditionally food and drink) to charity during Purim.
This year the celebrations, which follow the traditional Biblical calendar and so do not fall on the same day of our modern calendar each year, were held early, on Thursday, February 25, so the fast would not land on Shabbat (Sabbath or Saturday).
http://www.bridgesforpeace.com/
M V Tronson says that Purim not only acknowledges the story of Esther and the role she played in saving her people, it is a reminder of vigilance and the critical role that people in the right place at the right time have played throughout history.
He also makes the point that the book of Esther is unusual in that it is the only book of the bible that does not contain the name of G-d. (In Jewish tradition, the name of The Lord is never spoken or written). Mordecai does make a vague reference to the fact that the Jews will be saved by someone else, if not by Esther, giving the important message that can be gained from the story is that G-d often works in ways that are not apparent, in ways that appear to be chance, coincidence or ordinary good luck.
http://en.wikipedia.org/wiki/Book_of_Esther
"The African slave trade had its Esther in William Wilberforce. Apartheid in South Africa had its Esther in both Nelson Mandela and Archbishop Desmond Tutu," Mark Tronson notes.
He continues by saying that, in relation to the Jews of the Holocaust there were many 'Esthers' that saved either one single Jewish person, or thousands. If these people were Gentiles, they are commemorated as the Righteous among the Nations in Jerusalem, and if you visit that city you can see the trees planted in their honour.
http://en.wikipedia.org/wiki/Righteous_among_the_Nations
"Purim," he concludes, "is a reminder for us all, that vigilance against any sort of vicious control of any people group is a task that befalls us all. We need to maintain an alertness."
This message of Purim can also apply in principal to situations that are not life threatening; but situations where we see that people are simply acting politically to gain an advantage. Whether it is a P&C committee, a sports club, a Church or Mission, we can alert others to avoid the manipulation that can be enacted in the work place or wherever.
He also notes a more subtle message in Purim. The Jews were not actually saved from the ravages set by Haman – it was too late for the King to reverse the order to attack them. However, what he did was to allow them to defend themselves and this decision triumphed over Haman's men in the end. So, Mark Tronson thinks, the message here from the Bible is to alert people to any danger you see, and empower them to create their own defences, in their own way.