According to the official website, this holiday is held on Benjamin Franklin's birthday, January 17, because Franklin invented swim flippers while he was just 12 years old. (He invented a lot of things in his lifetime, of course!)
Check out the website for books, links, quotes, tips, and contests!
Here are some things invented by kids:
Popsicles (invented by an 11 year old)
Earmuffs (invented by a 15 year old)
Water skis (invented by an 18 year old, then consider a minor)
Television (kind of...this invention depended on a lot of efforts by a lot of people, but with a critical contribution from a 14 year old)
Also on this date: