Memorial Day was originally known as Decoration Day because it was a time set aside to honor the nation's Civil War dead by decorating their graves. It was first widely observed on May 30, 1868, to commemorate the sacrifices of Civil War soldiers...By the late 1800s, many communities across the country had begun to celebrate Memorial Day and, after World War I, observances also began to honor those who had died in all of America's wars. In 1971, Congress declared Memorial Day a national holiday to be celebrated the last Monday in May. (Veterans Day, a day set aside to honor all veterans, living and dead, is celebrated each year on November 11.)...Today, Memorial Day is celebrated at Arlington National Cemetery with a ceremony in which a small American flag is placed on each grave. Also, it is customary for the president or vice-president to give a speech honoring the contributions of the dead and lay a wreath at the Tomb of the Unknown Soldier.
Which reminds me: I'm still working on the American Culture tips I promised a while ago, so when they're finished, I'll alert the masses when the site is updated.