Date: March 5, 1770
The reality of it is less damning to the British than it sounds - what started as an argument about a wigmaker's bill (of all things) turned into a mob. Hundreds of Boston citizens kept 8 British Regulars cornered for hours. By the end of it, many were holding clubs, throwing stones, and taunting the soldiers to fire.
Captain Thomas Preston was in charge of the Regulars, and tried to defuse the situation by talking with the crowd. They asked if his soldiers' guns were loaded - he admitted they were, but it would have been stupid for him to order them to fire, since at the time he was standing in front of them.
It wasn't until one of the soldiers was hit by a stone (which forced him to drop his musket) that the Regulars fired into the crowd - against the orders of Preston, who later testified he never gave the command to fire. (It's possible his men mistook the taunts of the crowd for an order.)
The Regulars were arrested and tried for murder - six were acquitted, including Thomas Preston. The other two were found guilty of manslaughter, but had their thumbs branded in lieu of the usual sentence - which was death.
One of the interesting things about the massacre is what happened afterward - that is, how both sides tried to spin it to their advantage. The fact that most people call it a "Massacre" should give you some idea of who won this particular PR war. Revolutionaries portrayed it as an attack on Colonial liberties, and images of the event (popularized by Paul Revere), showed an organized British force firing into the crowd - not a confusing group of soldiers cornered by an angry mob.
The British, on the other hand, referred to the event "The Incident on King Street". We're naturally calm in a crisis - unlike countries who insist on turning every minor confrontation into a three-ring circus.
Anyway, the wigmaker dropped his prices and it never happened again.
I call it a victory for the bald.