The Biggest Dick Ever

A guy's walking along and sees a sign in a window that says, "$500 cash prize to anyone who can make my horse laugh." The guy goes in and asks to give it a try. He's in there 5  seconds and the horse just starts laughing out of control. The man walks out of the room and collects his $500.
A year  goes by and the same guy's walking by the same building, and  there's a new sign in the window.
And