I was listening in on an "adult" conversation when I heard the homophone "principal/principle" being misused. A man asked a question on which "principal/principle," he should use. A couple other people asked him, "well, use it in a sentence and we will tell you which one to use." The man said, "The main principal/principle I am trying to portray is..." Both adults that answered him said p-r-i-n-c-i-p-a-l! They said that the p-l-e one was the person in the school! I was so shocked that I didn't even try to correct them.
For anyone that may be wondering, principal means the most important position in an organization, or the principal in a school. Principle means a rule or law. And you would think that at least one of these three adults would have known that! Jeepers!