"Congressional sessions open with the recital of the Pledge, as do many government meetings at local levels, and meetings held by many private organizations. It is also commonly recited in school at the beginning of every school day, although the Supreme Court has ruled on several occasions that students cannot be compelled to recite the Pledge, or punished for not doing so."

"According to the United States Flag Code, the Pledge of Allegiance reads: I pledge allegiance to the Flag of the United States of America, and to the Republic for which it stands, one Nation under God, indivisible, with liberty and justice for all."

The "under God" part was added to distinguish us from 'godless communists'

http://en.wikipedia.org/wiki/Pledge_of_allegience

It's a grade school ritual that usually takes place once a week or so at the start of the day. Some teachers found this to be silly and were eager to make sure kinds knew it was voluntary or would come up with a better way to spend the three minutes. But some teachers would take it very seriously...