From the ArcaMax Publishing, Jokes Newsletter:
http://www.arcamax.com/news/jokes/s-365745-794545
A researcher arrives in Borneo to gather data for his thesis.
Accompanied by his trusty guide, he seeks out a very remote locale for
researching the mating behaviour of the giant rat of Sumatra.
Around dusk of the first day, he's sitting by the campfire with his
guide when in the distance, he hears tribal drums. They get louder.
The guide announces, "I don't like the sound of those drums."
The dusk turns evening. The drums get louder. The guide says, "I
really don't like the sound of those drums."
Evening turns to dead of night. The drums get louder and louder, until
it is obvious that the drummers must be quite close. The guide says
again, "I really don't like the sound of those drums."
Suddenly the drums stop, and a voice from the darkness cries out, "Hey
man, he's not our regular drummer!"