This was apparently researched by CNN, who asked many jokes to many people around the globe, and this was the most appealing:

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 takes 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 gunshot is heard. Back on the phone, the guy says: "OK, now what?"

It's quite funny, but nowhere near the best ever.

Anyone have any contenders for funniest?