Learning to Sign

This guy goes to the zoo one day. While standing in front of the
gorilla's cage, a gust of wind swept some dust into his eye. As he
rubbed his eyelid, the gorilla went crazy, bent open the bars, and
beat the guy senseless.
When the guy came to his senses, he reported the incident to the
zookeeper. Nodding, the zookeeper explained that pulling down your
eyelid means "F**k you! " in gorilla language. The explanation didn't
make the victim feel any better and he vowed revenge.
The next day he purchased two large knives, two party hats, two party
horns, and a large sausage.
Putting the sausage in his pants, he hurried to the zoo and over to
the gorilla's cage, where he tossed a hat, a knife, and a party horn.
Knowing that gorillas were natural mimics, he put on a party hat.
The gorilla looked at him, looked at the hat, and put it on. Next, he
picked up his horn and blew on it. The gorilla picked up his horn and
did the same. Then the man picked up his knife, whipped the sausage
out of his pants, and sliced it in half.
The gorilla looked at the knife, looked at his own crotch, looked at
the man, and pulled down his eyelid.