A short list below expanding upon cbeast's idea, hopefully to get your creative juices flowing: http://ideas4writers.wordpress.com/
- 50 years ago (19 May 1962)
American actress Marilyn Monroe famously sang ‘Happy Birthday’ to President John F. Kennedy during a birthday party/fundraiser at Madison Square Garden, New York City - 150 years ago (1 Jul 1862)
The Internal Revenue Service (IRS) was established in the USA, and the first national progressive rate income tax was introduced - 100 years ago (1 Jul 1912)
Birth of David Ross Brower, American environmentalist, founder of several environmental organisations including Friends of the Earth - 75 years ago (5 Jul 1937)
Spam luncheon meat was launched by Hormel Foods in Austin, Minnesota, USA - 70 years ago (6 Jul 1942)
Anne Frank and her family went into hiding in a secret annex at her father’s workplace in Amsterdam - 65 years ago (2 Jul 1947)
Roswell Incident, New Mexico, USA. A UFO apparently crash-landed on a ranch, and debris with strange markings and unusual properties was found. The U.S. Air Force claimed it was just a weather balloon - 50 years ago (2 Jul 1962)
The first Wal-Mart store opened in Rogers, Arkansas, USA - 40 years ago (1 Jul 1972)
The first Gay Pride march in Britain took place in London