A Self Sexist joke my uncle once told me:
So a man walks along the beach and sees a bottle, he opens the bottle and a genie pops out. The genie says, "I will grant you one wish." The man then looks around and notices a guy on the beach reading. With guys being so competitive and all, he says, "I wish I was ten times smarter then that guy over there." He got his wish and became ten times smarter.
A second guy walks along the beach and opens the bottle. When the genie says he can have one wish he looks around and sees the previous man reading on the beach. He then says to the genie, "I wish I was a hundred times smarter then that guy." The genie then made him one hundred times smarter then the previous man.
A third guy walks along the beach, sees the bottle, opens it, and the genie pops out. When the genie says he may have one wish, he turns around sees the last man reading on the beach. The man then says, "I wish I was a thousand times smarter then that guy!" The genie then turned him into a girl.