Besides being St. Patrick's day, it is also Purim.
And the king arose in his wrath from the wine-drinking and went into the palace garden, but Haman stayed to beg for his life from Queen Esther, for he saw that harm was determined against him by the king. And the king returned from the palace garden to the place where they were drinking wine, as Haman was falling on the couch where Esther was. And the king said, “Will he even assault the queen in my presence, in my own house?” As the word left the mouth of the king, they covered Haman's face. Then Harbona, one of the eunuchs in attendance on the king, said, “Moreover, the gallows that Haman has prepared for Mordecai, whose word saved the king, is standing at Haman's house, fifty cubits high.” And the king said, “Hang him on that.” So they hanged Haman on the gallows that he had prepared for Mordecai. Then the wrath of the king abated.
The sheer artistry of this turn of the plot and how everything in the story suddenly comes together is not always appreciated adequately, I think. What immediately leads to Haman's death, ironically, is begging for his life, an opportunity which he had not allowed the Jews. The whole episode is possible because Haman follows the advice of his advisors and wife to build the gallows to avenge himself on Mordecai (Est. 5:14) and fulfills the warning that Haman's advisors and wife had given him right before it happens when they learned that Mordecai, whom the king had just forced Haman to honor, was Jewish(Est. 6:13). Haman was so furious at Mordecai in the first place due to Mordecai's failure to bow down before him (Est. 3:5). But it's implied that Haman falls on the couch of Queen Esther, Mordecai's niece, from trying to bow down before her in begging for his life. Then Haman is hanged on his own gallows literally (the gallows themselves) and figuratively (his plot leads to his own death, and the gallows are the physical representation of his plot), which in the context of the whole story is itself clearly also more broadly symbolic (as representing the turning of the plots of enemies of the Jews in general against themselves), and thus he is executed at his own house on the charge of having assaulted the king's wife in the king's own house.