Patriot’s Day: Celebrated on the third Monday in April Patriot's Day commemorates the April 19, 1775 Battle of Lexington and Concord. If your American history is a little rusty, this battle began the Revolutionary War. It also honors the famous Midnight Ride of Paul Revere, who warned colonists that the British “Red Coats” were coming their way. As the story goes, on the evening of April 18 Thomas Gage, the British commander in chief of the Massachusetts Bay Colony was ordered to bring the colonies under control. Gage, in turn, ordered his men to destroy the Colonist’s war supplies in Concord and to capture Samuel Adams and John Hancock. However, the plans were leaked. So, today's lesser-known Wiliam Dawes and the well remembered Revere were sent to warn the Patriots, or Minutemen, as they were known in their day.
... The history books do not know who fired that first shot. What is known is that the war ended October 19, 1781 when the British surrendered to Gen. George Washington. A treaty between the two nations was finally signed in 1783. That, of course, lasted until the War of 1812.
Earth Day: Always April 22, Earth Day was first marked in 1970 by a nationwide environmental protest to “shake up the political establishment” and place it “onto the national agenda.” An estimated 20 million Americans took to the street in that protest. One result was the formation of The Environmental Protection Agency.
Arbor Day: Always the last Friday in April, National Arbor Day has been the tree planter’s holiday since 1872. It began in Nebraska, a largely treeless plain back in the 1800s. Today, all Americans can celebrate it by planting a tree. It is estimated that 18 million tress are planted each year on Arbor Day.
Administrative Professionals Day: Administrative Professionals' Day was originally organized in 1952 as "National Secretaries Day" by the National Secretaries Association in conjunction with a consortium of office products manufacturers. It was established as an effort to recognize secretaries for their contributions in the workplace. It is always observed on the last Wednesday of April, to recognize the work of clerical employees such as secretaries, receptionists, paralegals, and so forth.