America has been honoring members of the military currently serving by celebrating this holiday on the third Saturday in May since 1950.
The tradition began when President Harry S. Truman sought a specific day to honor all of our armed forces rather than have separate days for each individual branch. In August 1949, Defense Secretary Louis Jonson announced that Armed Forces Day would be created and celebrated the following May.
Contrary to Memorial Day celebrations next weekend, which remembers veterans that have died either in combat or from injuries sustained in war, Armed Forces is specifically for members of the military that are currently serving their country. In the past, America has celebrated with parades, picnics, concerts, and parties.