Just before the Battle of Actium:
Of Caesar they relate that, leaving his tent and going round, while it was yet dark, to visit the ships, he met a man driving an ass, and asked him his name. He answered him that his own name was Fortunatus, “and my ass,” he said, “is called Conqueror.” And afterwards, when he disposed the beaks of the ships in that place in token of his victory, the statue of this man and his ass in bronze were placed alongside them.
Having gone to an all-boys school, I can read this over and over again and still find it funny. From the Life of Antony. Up there with other great classic lines like “Abraham took his son Isaac and saddled his ass.”