Black Friday offered NBA fans in the Big Apple a rare treat: the chance to take in two games in one day. Between the Boston Celtics and Brooklyn Nets playing at Barclays Center on Friday afternoon and the Philadelphia 76ers and New York Knicks squaring off at Madison Square Garden on Friday night, fans could — if they chose — take in four of the five Atlantic Division teams simply by taking a quick subway ride. We did just that — and, in the process, got a chance to take a snapshot look at all four of them as the NBA season is 20% complete.