610: This is considered the traditional date when the prophet Mohammed begins to receive the Koran.
1519: Ferdinand Magellan's five ships set sail from Seville to circumnavigate the globe.
1628: The Swedish warship Vasa sinks in the Stockholm harbour after only about 20 minutes on her maiden voyage. Modern shipwrights feel that she had the same design flaws as the Mary Rose: too many guns place too high with not enough ballast. It was recently raised from the deep and restored to its former glory.
1675: The foundation stone of the Royal Greenwich Observatory in London is laid.
1776: Word of the United States Declaration of Independence reaches London.1792: The Tuileries Palace is stormed by revolutionaries. Louis XVI of France is arrested and taken into custody. This is considered to be the official end of the French monarchy, until its restoration in 1814.
1821: Missouri is admitted as the 24th state.1846: Congress charters the Smithsonian Institution, named after English scientist James Smithson, whose bequest of $500,000 made it possible.
1856: William Willett is born. He invented Daylight Saving Time.
1874: Herbert Hoover is born.
1879: Charles Darrow, the alleged inventor of Monopoly, is born. Modern evidence indicates that he stole the idea whole cloth from somebody else but it's still one of my favorite boardgames. 
1898: Jack Haley is born. He played the Tin Man in The Wizard of Oz.1902: Curt Siodmak is born. He wrote the novel Donovan's Brain, one of the early forays into the "brain-in-a-jar" genre.
1921: Franklin D. Roosevelt is stricken with polio at his summer home on the Canadian island of Campobello.
1928: Jimmy Dean, country singer and sausage magnate, is born.
1939: Kate O'Mara is born. She played a slew of femme fatales in horror movies produced by Hammer Studios and the wicked Time Lady Rani in a few episodes of Doctor Who. She was in, maybe, two episodes total and has become a fan favorite, even subtlely working her way into the New Who (against the producers' wishes). That just goes to show you: nerds love bad girls.
1948: Candid Camera makes its television debut after being on radio for a year as Candid Microphone.
1949: President Harry S. Truman signs the National Security Act Amendment, streamlining the defense agencies of the United States government, and replacing the National Military Establishment with the United States Department of Defense.
1969: A day after murdering Sharon Tate and four others, members of Charles Manson's cult kill Leno and Rosemary LaBianca.
1971: The Society for American Baseball Research is founded in Cooperstown, New York.
1988: President Ronald Reagan signs the Civil Liberties Act of 1988, providing $20,000 payments to Japanese-Americans who were either interned or relocated by in the United States during World War II.
Today in History elements mostly cribbed from The History Channel, Wikipedia, The New York Times, The Jewish World Review, The Writer's Almanac and anything else I can dig up.
