There were initially only supposed to be 25 Federalist Papers, but John Jay ended up writing 5, James Madison wrote 29, and Alexander Hamilton wrote a whopping 51 essays. We'd need to have ten times the amount of coffee than he even had access to at the time in order to do that. (Source) 

Alexander Hamilton at the Constitutional Convention spoke for a whopping six hours straight, outlining his vision for the Federal Government. After his ideas, such as his idea that the Presidency should be an immensely powerful life-long office, were met with disapproval, he left the Convention entirely. After that, if delegates at the Constitutional Convention had gripes about the Constitution, they could say, "Hey- At least it wasn't that Hamilton guy's nutso plan." (Source)

It's not surprising, especially to people living in Washington, that a lot of things got named after the Founding Fathers. Our pal Madison got his name on Madison Square Garden, the huge arena in New York City, among other things. (Mendelsohn, Joyce. "Madison Square." The Encyclopedia of New York City. Ed. Kenneth T. Jackson. First Edition. New Haven: Yale University Press, 1995. ISBN 0300055366, p. 711–712)

Hamilton came up for the idea for the Federalist Papers while on a boat ride from Albany to New York City. By the time he landed, he had already drafted an outline for the essay series and the first essay. Note to self—do more work on boats. (Source)

Publius was actually an old pen name of Hamilton's, which he first used to write an article to slam Samuel Chase. Ironically, Chase would go on to be the first Supreme Court Justice to cite the Federalist Papers in the Supreme Court. Man, can you imagine the look on his face when he saw that signature for the first time? (Source)