Defenestration of Prague

The Second (and most famous) Defenestration of Prague referred to this historical act of throwing someone out the window:

At Prague Castle on May 23, 1618, an assembly of Protestants (led by Count Thurn) tried two Imperial governors, Wilhelm Grav Slavata (1572–1652) and Jaroslav Borzita Graf Von Martinicz (1582–1649), for violating the Letter of Majesty (Right of Freedom of Religion), found them guilty, and threw them, together with their scribe Philip Fabricius, out of the high windows of the Bohemian Chancellery. They landed on a large pile of manure and all survived unharmed. Philip Fabricius was later ennobled by the emperor and granted the title "von Hohenfall" (lit. translating to "of Highfall").

Because of its reference to window, it is also a slang for "completely removing Microsoft Windows from a PC in favor of a better OS, typically Linux" or "to drag something, like an icon, out of a window and onto a screen"

Link: Defenestration of Prague - via Scribal Terror