A guy walking down a street one afternoon passes an old man sitting on the side of the road with a large sack.
The younger guy says to the old man, "Watcha got in the sack?"
The old man responds, "I got some monkeys in that there sack."
The younger man asks, "If I guess how many monkeys you got in the sack, can I keep one?"
The old man replies, "Son, if you guess how many monkeys I got in this sack, I'll give you both of 'em!"