An expression of disbelief, shock, and utter surprise. Often heard after witnessing an incredible feet, or something that is downright amazing. However, it can also be used in the negative, when one encounters bad luck.
When Dad saw the skier land the two flips, he turned to me and said, "Shit a monkey, did you see that?!"
Dad muttered 'shit a monkey' when he saw that the tire had been punctured.