Does laughter burn calories?

I have this friend who is easily seduced by new-fad-diet books, which I generally make fun of because they're so outrageous.

S/he has a new one called "The Flat Belly Diet," which I quickly renamed "The FAT Belly Diet". There's a four-day cleansing period in which you eat and drink very little ... including lots of what they call "Sassy Water." I have to admit this stuff sounds pretty good: Mix 2 liters of water with grated ginger root, sliced cucumber, lemon juice and mint leaves, then let it si