the Defenestration of Prague, a central event to the start of the Thirty Years’ War. and somehow, i’ve managed to retain this information from high school A.P. Euro (probably because it’s an amusing way a war—one lasting 30 years—began; you can’t make this shit up [hah, pun!]). learn more about it on Wikipedia.
defenestration (n): the act of throwing a person or thing out of a window.