Hacham Ovadia Yosef, in his work Hazon Ovadia (Purim, p. 207), addresses the case of a person who became inebriated on Purim, and as a result of his spirited singing and dancing he caused damage to his fellow or to his fellow’s property (such as staining his clothing). One might have thought that the individual does not bear liability, since the damage was caused by his involvement in the Misva of Purim celebration. However, Hacham Ovadia rules that Halacha draws no distinction between Purim and other days of the year with regard to liability for damages. One who causes damage as a result of the Purim festivities is no less liable to compensate the victim than he would be on other days of the year.
Earlier, Hacham Ovadia addresses the question of whether one may get married on Purim. He cites the ruling of the Shulhan Aruch (Orah Haim 696:5) that weddings may be held on Purim day, and even the festive meal after the wedding ceremony may take place on Purim (listen to audio recording for precise citation). Celebrating a wedding on Purim does not violate the Halachic principle of "En Me’arbin Simha Be’simha," which forbids combining two different celebrations. Nevertheless, Hacham Ovadia writes that as a "Midat Hasidut" (measure of piety), one who gets married on Purim should conduct the festive celebration only at night, after Purim has ended.
Summary: One who causes damage to his friend or his friend’s property as a result of the Purim festivities is liable for the damages. It is permissible to get married on Purim, though the wedding meal should preferably be delayed until the nighttime, after Purim has ended.