This is the question that the Applied Math guys worked on yesterday. (I got the question from Number Freaking, an excellent book. Go buy it!)
Some good comments/questions from the students: “I talk a lot more than 60 minutes a day, and probably faster than 2 words per second”, “I wasn’t talking for the first two years of my life, so do I have to add that in?”, and “What about leap years?”. I didn’t directly answer any of their questions, and I only showed my calculations after they had all committed to a result and put it on the whiteboard.
Nice activity for a throwaway 20 minutes at the end of class.