What makes a party a disaster? I once threw a party in which more than a dozen attendees were arrested, and I was evicted, as well as two neighbors. They're still talking about that one more than 40 years later. But it wasn't as bad as the event President Francisco Macías Nguema of Equatorial Guinea threw for Christmas in 1969. He invited 150 of his political opponents to a football stadium, and his guards (who some say were dressed as Santa Claus) shot and killed them all.
Other world leaders threw or attended Christmas parties that turned out to be disasters of one sort or another. Sometimes people got killed, while others were just embarrassing. Winston Churchill invited himself to a White House Christmas party in 1941. The King of Sweden's Christmas banquet in 1317 was the last time anyone ever saw his brothers. And then there was Jimmy Carter's hemorrhoids. Read about all these Christmas parties and more at Mental Floss.