This holiday was created in 2007, by Shari Arison, a businesswoman and philanthropist. Last year, Arison was named one of the World's Most Powerful Women by Forbes Magazine. Her motto is "think good, speak good, and do good"
So on this day, think what good deed can you can do for someone. Then go and do it!
You can read about Good Deeds Day at the Huffington Post Blog.