Grandparents' Day

1. National Grandparents Day originated with Marian McQuade, a housewife in Fayette County, West Virginia and has been recognized nationally by the United States Senate – in particular by Senators Jennings Randolph; and Robert Byrd – and by President Jimmy Carter, as the founder of National Grandparents Day.
2. Her primary motivation was to champion the cause of lonely elderly in nursing homes and she also hoped to persuade grandchildren to tap the wisdom and heritage their grandparents could provide.
3. McQuade made it her goal to educate the youth in the community about the important contributions seniors have made throughout history and she also urged the youth to "adopt" a grandparent, not just for one day a year, but rather for a lifetime.
4. The celebration not only honors grandparents for nurturing their children’s children, but makes grandchildren aware of the strength and guidance older people can offer.
5. Some people claim the origin of the holiday resides with the efforts of Hermine Beckett Hanna of North Syracuse, New York, recognizing seniors and their importance as early as 1961. On February 21, 1990, New York Congressman James T. Walsh recognized the efforts of Hermine Beckett Hanna in front of the U.S. House of Representatives, thanking her "for her important role in the establishment of Grandparents' Day".
6. In 1973, Senator Jennings Randolph (D-WV) introduced a resolution to the senate to make Grandparents' Day a national holiday. In February 1977, Senator Randolph, with the concurrence of many other senators, introduced a joint resolution to the senate requesting the president to "issue annually a proclamation designating the first Sunday of September after Labor Day of each year as 'National Grandparents' Day'."
7. Congress passed the legislation proclaiming the first Sunday after Labor Day as National Grandparents' Day and, on 3 August 1978, then-President Jimmy Carter signed the proclamation. 
8. The statute cites the day's purpose: "...to honor grandparents, to give grandparents an opportunity to show love for their children's children, and to help children become aware of strength, information, and guidance older people can offer".
9. In 2004, the National Grandparents' Day Council of Chula Vista, California announced that "A Song for Grandma and Grandpa" by Johnny Prill would be the official song of the U.S. National Grandparents' Day holiday.
10. Since 1999, the official flower of the U.S. National Grandparents Day is the forget-me-not which blooms in the spring.
11. Countries that celebrate this day are the United States, the United Kingdom, Canada, India, Australia, France, Italy, Poland, Estonia, Singapore, Taiwan, and the Philippines.
12. The Philippines started to celebrate Grandparent’ Day in 1987, which it adopted from the United States.  

References:

Special treats for grandpa and grandma
Grandparents Day Greetings
National Grandparents Day
In 2014, Grandparents Day falls on Sept. 7th
Celebration: Happy Grandparents’ Day!