All due respect to Macbeth, who uttered his immortal soliloquy in an understandably bad mood , but our days, while not as unique as snowflakes, do exhibit considerable variability over time. A man who had just lost his wife, his "dearest partner of greatness," should have been more sensitive to the fact that he was having an exceptionally bad day. Ah, but such is grief.

This holds true even for Christmas, surely one of the most tightly scripted days in our calendar, owing to religious custom, secular tradition, achingly familiar sights, sounds and smells and a general lack of creative imagination on our parts.

Still, enough memorable stuff—weird, unique, important or just sensory-invading—happens on enough Christmases that we can generally think back and recall distinctive memories of different Christmases without trouble. Much of what makes stuff stick in our mind on this day doesn't even have much, or even anything, to do with Christmas. Some of it is bad, some good, most of it is just, well, stuff.

Some things are life-altering. Some change the path of history. Some just fill up our time. But they just happen to fall on a day we thought we'd reserved for other purposes, and that's how we remember those days.

On Christmas Day in 800 AD Charlemagne (Charles the Great, King of the Franks) was crowned first Emperor of the Holy Roman Empire by a grateful Pope Leo III. That was a memorable day. Charlemagne had restored the pope to power by putting down a rebellion that had forced the latter out of Rome. A far-thinking visionary and highly competent ruler, Charlemagne basically unified Europe and pulled the continent out of the Dark Ages and a cultural stagnation that didn't look like it was ever going to end.

On Christmas Day 1066, William, Duke of Normandy was crowned king of England at Westminster Abbey in London. He was better known as William the Conqueror. His coronation came after his legendary invasion of the British Isles, which had culminated in October 1066 with a victory over King Harold II at the Battle of Hastings.

On Christmas Day 1642 (according to the calendar being used at the time), Sir Isaac Newton was born. The English scientist who first identified gravitational forces, he was also a pioneering mathematician and researcher in the field of optics.

On the evening of December 25, 1776, General George Washington crossed the Delaware River to carry out a surprise attack on British lines. Colonial troops caught Hessian mercenaries (employed by the British) groggy and unprepared for a fight, just as a terrible winter storm was setting in.

The attack became known as the Battle of Trenton and was of huge significance to the fledging nation, raising the troops' spirits and reviving the hope among colonists who were beginning to fear success in their fight for independence wasn't feasible.

Christmas 1814 heralded not just the birth of the Christ child but quite literally peace on earth or at least on part of it. On December 24, 1814 the United States and Great Britain signed the Treaty of Ghent, which ended the War of 1812.

Historically speaking, it was not really a seminal moment. Negotiations had begun earlier that August—the same month in which British forces burned the White House and the U.S. Capitol. The settlement essentially called the war a draw. (In Latin: "Status quo ante bellum").

All conquered territories were relinquished, and captured soldiers and vessels were returned to their respective nations. The Treaty did not take effect in the US until it was ratified in February 1815. One of the greatest American victories of the war (the Battle of New Orleans) took place more than a week after the treaty was signed.

What Americans regard as a critical test in our early fight for national survival was really just a local skirmish in a far larger global conflict, which raged from 1789 and 1815 and stretched from Europe to North Africa and even Asia. We remember that Christmas it for that probably more than people in other countries do.

The combatants were the French Empire and varying coalitions that included Great Britain, Russia, Prussia, and Austria and virtually everyone else that Napoleon hadn't already conquered.

The War of 1812 marked the first time the U.S. declared war as a nation, and it was against a country that regarded the conflict as a pesky distraction.

On Christmas Day 1868, at the tail end of his term, President Andrew Johnson issued an amnesty proclamation to "all and every person" who had fought against the United States during the Civil War.

This pardon was actually the fourth in a series of orders dating back to May 1865, which had restored legal and political rights to Confederate soldiers in exchange for signed oaths of allegiance to the United States. Those pardons had excluded 14 classes of people including certain officers, government officials and those with property valued over $20,000.

The Christmas pardon was a final and unconditional act of forgiveness for unreconstructed Southerners, including many former Confederate generals.

On Christmas Eve in 1818 "Silent Night," the hauntingly beautiful holiday carol that has been sung at Christmastime for close to 200 years now, was first performed in public . Known as 'Stille Nacht! Heilige Nacht' in German, it was first performed in the Austrian village of Oberndorf at a Midnight Mass in the church of Saint Nicholas.

On Christmas Day 1896, John Philip Sousa composed the melody for "Stars and Stripes Forever" while crossing the Atlantic on his way home from a European vacation. Sousa grew up during the Civil War to become a long-time director of the U.S. Marine Band.

Sousa was a rock star of his time, eventually starting his own band in 1892. The iconic song officially became America's national march in 1987.

On Christmas Eve 1914, early in World War I, scores of German, British and French troops in Belgium dropped their weapons and began a spontaneous holiday ceasefire. The "Christmas Truce" was reportedly initiated by the Germans, who decorated their trenches with Christmas trees and candles and began singing carols like "Silent Night." British troops responded with an English version of "The First Noel." The combatants eventually ventured into the bombed-out space that separated the trenches to greet and shake hands.

They shared cigarettes and whiskey and some exchanged Christmas presents, men they had been shooting at each other hours before. Some Scottish, English and German troops organized a pick-up soccer game on the frozen battlefield. The truce was not sanctioned by officers on either side, and eventually the men were called back to their trenches to resume fighting. Similar future holiday meetings were mostly forbidden.

The night before Christmas 1968, Apollo 8 astronauts Frank Borman, Jim Lovell and William Anders spent their time orbiting the moon. Their mission achieved a series of breakthroughs in manned space flight. They became the first men to leave Earth's gravitational pull, the first to orbit the moon, the first to view all of Earth from space and the first to see the dark side of the moon.

In a special live Christmas Eve TV broadcast, Borman, Lovell and Anders read the opening lines of the book of Genesis. The broadcast became one of the most watched television events in history.

On December 24 and 25, 1979, the USSR began deploying military equipment and personnel into Afghanistan. The Russians and their allies chose this time of year trusting the rest of the world would be busy celebrating Christmas, which would delay any diplomatic or military response to the incursion. Russia withdrew in 1989 after accomplishing little at great expense. The occupation has been referred to as the "Soviet Union's Vietnam War," and it is thought by many to have been a contributing factor to the Soviet Union's fall. To this day U.S. troops are still celebrating Christmas in Afghanistan following the U.S. invasion of that country after the September 11 attacks in 2001,

On Christmas Day 1990, the Internet got its first test run when info.cern.ch, the planet's first web server went live.

On Christmas Day 1991, Mikhail Gorbachev resigned as President of the Soviet Union. At the time, the Soviet Union (now broken up into Russia and other republics) was considered America's most formidable enemy. That began to change in the late 1980s, with the Gorbachev's policy termed Glasnost. But maybe not for good.

This policy instituted greater transparency in government institutions and activities and encouraged open discussion of political and social issues and the problems of the country's system. It was first instituted in the late 1980s and began the democratization of the Soviet Union. While it led to more personal freedom for Russian citizens, it also led to the eventual disintegration of the Soviet Union itself.

Gorbachev basically was cast aside by the leaders of the various republics whose positions, owing mainly to his political reforms (and some bad central economic policies), had grown to the point where their power superannuated his own. Vladimir Putin believes to this day the dissolution was one of the greatest disasters in Russian history.

So have yourself a Merry, Merry Christmas. Have yourself a good time. But just remember, somebody may be out there actually doing something while you're drinking down your wine (apologies to The Kinks). Something you're likely to remember through the haze of many, many Christmases to come.

Or not. Doesn't happen every year, after all.