Memorial Day was originally called Decoration Day. This is a day set aside for remembrance of those that have lost their lives in service of the United States.
It was borne out of the Civil War and a desire to honor those that have died. The date was chosen because it didn't mark the anniversary of any battle. This was to be a day given only to the respect and honoring of the dead.
National Moment of Remembrance
This resolution was passed in December 2000. It asks that at 3:00 pm, local time, for all Americans "To voluntarily and informally observe in their own way a Moment of Remembrance and respect, pausing from whatever they are doing for a moment of silence or listening to Taps."