An American couple on vacation with some friends in Mexico were shopping at the market to bring back a few souvenirs to their family and friends. The time passed and the couple realize that neither of them were wearing watches. They noticed this Mexican man laying down taking a siesta next to this mule that had the largest set of mule nuts they had ever seen.
Trying not to stare at the huge mule nuts they asked the Mexican man, "Excuse us could you tell us what time it is?"
The Mexican man reaches his hand out under the enormous set of nuts lifting them high and says, "It's 3 o'clock."
Amazed by this the American couple go off to find their friends and tell them the amazing story. This Mexican man over there can tell time by lifting his mules balls! Curious and amazed by this the friends want to see first hand so they go back and ask him what time it was.
Sure enough the Mexican man reaches out again cups his hands under the mules nuts lifts them up as if to weigh them and says, "It is 3:15." Their friends check the time on their watches and sure enough the little man was correct.
Blown away by this finally the American couple ask, "It is just amazing how do you do that?"
"Do what?" the Mexican asks.
"Tell the time by lifting your mule's balls!"
"Ah," Says the Mexican, "I just need to lift his balls so I can see that big clock across the street."