Joshua A. Norton was a pretty interesting character from San Francisco's history. He was a businessman who tried to get a monopoly on rice in 1854 by buying up all the rice in the city, but then lost everything when two Japanese ships arrived in the harbor full of rice...this disaster apparently caused some kind of mental breakdown (or maybe just the decision to live life as an eccentric), because in 1859 he brought a note to the San Francisco Bulletin declaring himself Emporer of the United States, which they published the next day (he later added 'Protector of Mexico' to his official title). He spent the rest of his life issuing decrees (like one disbanding Congress, and another ordering the construction of a suspension bridge across San Francisco Bay), mingling with his subjects in his official blue and grey uniform (to support both the Union and the Confederacy) and feathered hat, and printing his own money to cover living expenses, which local businesses would often accept out of civic pride (he also allowed some of them to put up signs that said 'By Appointment of His Emperor, Joshua Norton I'). The city also had him march at the front of the annual police parade, and gave him his own bicycle, shown above. According to this page, Mark Twain worked right next to Norton's boarding house and "claimed that the man wasn't so insane as people thought", and supposedly also based the character of "The King" in Huckleberry Finn on him. Norton also corresponded with fellow heads of state like Lincoln and Queen Victoria. He died in 1880 after a 21-year-reign, prompting the San Francisco Chronicle to run an obituary titled Le Roi Est Mort.

Other Norton links:
Emperor Norton bibliography
1923 article on Norton from California Historical Society