History is what I'm theoretically studying in school, but I've learned nearly nothing, so I'm here to share some of that nothing with you! One of my few points of pride in life is that I wrote the Wikipedia article on noted obscure history event the Straw Hat Riot, which took place in New York in 1922. About 1000 people brawled throughout the streets of New York, because some of them were wearing straw hats.
First, a little background. I read Neil Steinberg's excellent book Hatless Jack, which is just a top-notch book about the history of hats. Second to none. The most important point Steinberg gets across is that, until about the 1960s, hats were mandatory. It's hard to imagine that now, but a bare head outdoors tended to symbolize that you were either a boor or homeless. Hats were incredibly important, then, and there was some ettiquette rules when it came to the wearing of them. One of these rules was more of an unspoken, unofficial "don't wear white after labor day" kind of thing: you couldn't wear a straw hat past September 15th. Straw hats were summer hats. If you wore one past this date, strangers were liable to playfully knock it off your head, you fashion-ignoring idiot. [A particularly amusing example of people's chagrin towards violators of this rule comes from an NYT article from the era about Coolidge, who apparently just couldn't get with it. It goes without saying that I would like there to be more news articles about the President's fashion faux pas these days.]
Here's where things get less playful. In New York in 1922, a group of young folks who were up to no good decided to start knocking hats off a few days early, and even smashing those hats. These hooligans went around smashing hats left and right, until they met some surly dockworkers who didn't take kindly to their hats being ruined, and a big fight broke out. Police broke up these fights, but the next day, a full-on war had broken out, with gangs of roving youths running through the city and smashing hats [and sometimes the heads of wearers]. It's estimated that 1,000 people were involved in this massive fracas. There were a bunch of injuries and some arrests. All over hats.
Now, what does this all mean, in the greater scheme of history? Absolutely nothing. There were a couple smaller straw hat riots, and the whole "unwritten rule" thing is kind of cool, but this is essentially an isolated event that had no effect on history as we know it. And that's the kind of history I know about.
For more info on the Straw Hat Riot, visit your local library.