Sources:

http://en.wikipedia.org/wiki/Flag_Day_in_the_United_States
http://en.wikipedia.org/wiki/United_States_Flag_Code

Video Tutorial on US Flag Code

↓ Transcript
Fact of the Day:
On June 14, 1777, the US Congress adpoted the Stars and Stripes flag for the United States of America.
The first flag had 13 stars in a circle where there are now 50 stars. Each star represents a state and there have been many designs for the stars as states were added.
Happy birthday United States flag!