Sam & Flavius Clemens

One of Mark Twain's favorite books was Suetonius' Lives of the Caesars. According to Twain's biographer, Albert Bigelow Paine, he carried it around and read it until his very last day.

Near the end of the book, Suetonius tells how the Emperor Domitian put to death many people including his own cousin Flavius Clemens, a man "below contempt for his want of energy." (Latin "contemptissimae inertiae...") In the margin of his well-thumbed copy of the book, next to the name "Clemens" and the words "want of energy", Mark Twain wrote "I guess this is where our line starts."

This is amusing because:

A. Mark Twain's real name was Sam Clemens
B. Mark Twain was famous for his want of energy.

Lazy Jim & Huck from The Adventures of Huckleberry Finn