January 21st

2010
In a 5-4 decision, the U.S. Supreme Court rules in Citizens United v. Federal Election Commission that the government cannot restrict the spending of corporations for political campaigns, maintaining that it's their First Amendment right to support candidates as they choose. This decision upsets two previous precedents on the free-speech rights of corporations.
Citizens United v. FEC
2008
Black Monday in worldwide stock markets. FTSE 100 had its biggest ever one-day points fall, European stocks closed with their worst result since 9/11, and Asian stocks drop as much as 15%.
Black Monday (1987)
2004
The recording industry sued 532 computer users it said were illegally distributing songs over the Internet.
Timeline of file sharing
2003
The Census Bureau announced that Hispanics had surpassed blacks as America's largest minority group.
Demographics of New York City
1998
Pope John Paul II visits Cuba. It was the first time any Pope visited the country.
Religious views of Fidel Castro
1997
Speaker Newt Gingrich was reprimanded and fined as the House voted for first time in history to discipline its leader for ethical misconduct.
Wikipedia:Reference desk archive/Humanities/April 2006
1994
A jury in Manassas, Va., acquitted Lorena Bobbitt by reason of temporary insanity of maliciously wounding her husband, John, whom she'd accused of sexually assaulting her.
John and Lorena Bobbitt
1977
President Jimmy Carter pardoned almost all Vietnam War draft evaders.
Jimmy Carter
1976
Concorde takes off on its first scheduled flights. 2 of the supersonic aircraft took off from Paris and London simultaneously.
Concorde
1968
Vietnam War: Battle of Khe Sanh - One of the most publicized and controversial battles of the war begins.
Tet Offensive
1954
The first atomic submarine, the USS Nautilus, was launched at Groton, Conn.
USS Nautilus (SSN-571)
1950
A federal jury in New York City found former State Department official Alger Hiss guilty of perjury.
Alger Hiss
1924
Russian revolutionary Vladimir Ilyich Lenin died of a stroke at age 53.
Vladimir Lenin
1915
The first Kiwanis Club was founded, in Detroit.
Kiwanis
1911
23 cars take part in the first Rally Monte Carlo. Unlike today, the competitors set out from 11 different European locations, heading for the finish line in Monte Carlo.
Monte Carlo Rally
1899
Opel builds its first automobile. Today, Opel is one of the world's largest car manufacturers.
Opel
1861
Five Southerners resigned from the U.S. Senate, including Jefferson Davis of Mississippi, the future president of the Confederacy.
Jefferson Davis
1793
Louis XVI of France is executed by the guillotine in Paris, following his conviction for high treason.
Execution of Louis XVI
1525
The Swiss Anabaptist Movement is born when Conrad Grebel, Felix Manz, George Blaurock, and about a dozen others baptize each other in the home of Manz's mother in Zürich, breaking a thousand-year tradition of church-state union.
1525