Every schoolchild in the United States starting at the age of ~six is expected (but not legally required) to participate in a daily recitation of the Pledge of Allegiance.
"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."
There are a number of obvious questions about the ethics of indoctrinating children with this sort of thing, but that is left as an exercise for the reader.