Groaning Oldies

From Friar's Club Encyclopedia of Jokes by Barry Dougherty.

This guy went to the zoo one day. While he was standing in front of the gorilla’s enclosure, a gust of wind blew some grit into his eye. As he pulled his eyelid down to dislodge the particle, the gorilla went crazy, bent open the bars, and beat the hapless fellow senseless. When the guy came to, the zookeeper was anxiously bending over him, and as soon as he was able to talk he explained what had happened. The zookeeper nodded sagely and explained that in gorilla language, pulling down your eyelid meant “fuck you.”

The explanation didn’t make the gorilla’s victim feel any better, and he vowed revenge. The next day he bought 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, into which he tossed a hat, a knife, and a party horn. Knowing that the big apes 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 neatly in two.

The gorilla looked at the knife in his cage, looked at his own crotch, and solemnly pulled down his eyelid.