There was a guy who walked into a bar and said to the bartender, “I’ll bet you a beer that I can bite my left eye.” The bartender said, “Well, nobody can bite their own eye!” So the man took out a glass eye and bit it. He got his free beer from the bartender who had just lost the bet. Then he said, “I’ll bet you another beer I can bite my right eye.” The bartender replied, “No one can have two glass eyes.” So the man took out false teeth and bit his left eye.
