Laughter-Jogging for the Soul?

When Mathematicians Laugh

We saw a billboard touting the benefits of laughter-- "Jogging for the mind" or for the soul. Either way, it's probably good for you. Even as one who has been told by physicians that I should not jog or run because of back and knee problems, I can still laugh. I try to now and again, hopefully at appropriate times and for appropriate reasons.
   You might notice a couple of little jokes in the "mathematical formula". I'm sure the formula doesn't add up or reflect actual math. Come to think of it, most of my high school math homework didn't either. There were cartoons drawn in the margins though....