According to The History Channel Magazine, a recent survey by the McCormick Tribune Freedom Museum found that "only 28 percent of Americans are able to name more than one of the five First Amendment freedoms guaranteed by the U.S. Constitution, compared with 52 percent of all Americans who could name at least two Simpsons" (from the animated TV series The Simpsons). To be honest, I was more surprised that 48 percent of Americans couldn't name two Simpsons.

By the way, the First Amendment freedoms are the freedom of speech, religion, the press, assembly and petition for redress of grievances (I didn't remember that last one).