What's so funny?

They say that laughter is the best medicine. Like many pharmaceuticals however, there is the danger of overdosing. I once read about a man who died while watching Seinfeld: he laughed so much he had a stroke or a heart attack or aspirated a peanut or something like that. I almost died laughing when I heard this, although I'm sure the man's family was not amused. Laughing is highly infectious and often leads to decapitation or exploding intestines, although there are those who have a natural immunity to the bug. According to the dictates of natural selection then, unless we develop an effective vaccine the human race will eventually evolve into a dour lump, except in those places where The Origin of Species has been thrown on the burning book pile. Or maybe some dour lump, too impatient to wait for evolution, will devise a humourous eugenics plan involving this weapon of mass destruction (which, contrary to Dick Cheney's assertions, was hidden in Youtube, not Iraq).

Joking aside, laughter has been the subject of some serious research carried out by Dr. Richard Wiseman and The British Association for the Advancement of Science. They set out to find the funniest joke in the world. Here it is:

Two hunters are out in the woods when one of them collapses. He doesn't seem to be breathing and his eyes are glazed. The other guy whips out his phone and calls the emergency services. He gasps, "My friend is dead! What can I do?". The operator says "Calm down. I can help. First, let's make sure he's dead." There is a silence, then a shot is heard. Back on the phone, the guy says "OK, now what?"