Weekend Trivia Challenge for 5/13/16

This champion of yesteryear was lucky enough to live to an advanced age---33---but the guests at his final birthday party were less fortunate, largely due to their own overindulgence after having tried to drink a toast to every year of the horse's age and then some. While no one died as a result of this epic bash, the horse was one of the few at the celebration not suffering from a monumental hangover the next day. Who was the equine guest of honor at this memorable gala?