Boston Massacre

A precursor to the American Revolution in 1770. There was huge anti-British feeling in Boston and a large garrison of redcoats. The days before had witnessed many huge brawls between British soldiers and colonists. British soldiers were taunted by a crowd of American colonists. The crowd yelled that if the soldiers shot, they couldn't kill all the colonists, and chanted "Fire and be damned!" The soldiers got mad and fired upon the Americans. Five were slain. Paul Revere made a famous engraving immortalizing this event.

Despite public feeling, the radical John adams, future US president, agreed to defend the soldiers. Sam Adams, John's cousin, was the first to lead the cry for revenge, joined by John Hancock and Paul Revere. War would break out 5 years later.

Tradition says that these five were the first to die for freedom in the american Revolution.

Interestingly, the Boston Massacre began with a snowball fight. On March 5, 1770, a gang of sixty Bostonians gathered outside the customs house and surrounded the British sentries standing guard. It wasn’t long until the tensions escalated to such an overwhelming level that, God help us, the colonists began to pelt the redcoats with snowballs. Not exactly your traditional brazen act of political rebellion.

What started as a schoolyard snow brawl, however, grew to something far more serious. One of the sentries fired a shot and it spurred the brutal gunfight that killed five colonists and served as a catalyst to the forthcoming American Revolution.

However significant, it was really more of a street fight than an actual massacre, at least by my standards. But colonial patriots such as the Sons of Liberty were quick to give the event the name by which it is now remembered. Big flashing titles like "massacre" inspire a lot more passion in a populace you're hoping to nudge towards revolution than less emphatic monikers do. The Boston Customs House Squabble? I think not.

Sources:
http://www.multied.com/revolt/Massacre.html
http://en.wikipedia.org/wiki/Boston_Massacre
And my faithful history textbook (Canada: A North American Nation by Bennet, Jeanen and Brune.)