A guy walks into a bar.
Guy: "Hey, barkeeper, give me a beer."
Barkeeper: "Tell you what, if you can make that horse out there laugh, I will give you a free beer and $500."
So the guy walks outside and whispers to the horse. The horse laughs. The guy walks back in.
Guy: "Where's my $500 and free beer?"
Barkeeper: "Alright, double or nothing says you can't make that horse cry."
The guy walks outside again. The barkeep chuckles to himself as he's cleaning a glass and misses what the guy does, but he hears the horse crying. The guy comes back in.
Guy: "Alright, where's my $1000 and two free beers?"
Barkeeper: "What did you say to make the horse laugh?"
Guy : "I told him I have a bigger penis than him."
Barkeeper: "What did you do to make him cry?"
Guy: "I showed him."