Passersby in Washington Square Park on Fri., Dec. 13, might have wondered whether Colin Huggins, a.k.a. “The Crazy Piano Guy,” was, in fact, crazy to be out there as the mercury hovered around the freezing point. Although he had on his trusty ear-flaps hat, he was playing without even half-gloves on his hands. At least he was working in some faster classical numbers to keep the blood flowing to his tattooed fingers. In between performances, he was offering his CD (seen inside the piano) for sale.