Pearls of Teenage Wisdom

Me: "Remember, 'a lot' is two words. Every time I see it written as one word, I sprout another gray hair."
Student: "You don't have any gray hairs. Oh, wait. I see them now."

With another class later that very same day...

Me: "And what was the name of the mountain where the shepherd found Oedipus?" (The correct answer is "Mount Citheron.")
Student shouting from the back with complete sincerity: "Mount Syphilis!"
Another student, also with complete sincerity: "Really? I thought that was something else."