The NFL’s regular season ended Sunday with one coach, Indianapolis’s Chuck Pagano, making a triumphant and inspiring return to the sidelines after months of cancer treatments. Meanwhile a handful of coaches were about to receive pink slips (Philadelphia’s Andy Reid, Kansas City’s Romeo Crennel, Cleveland’s Pat Shurmur, and Buffalo’s Chan Gailey were gone by Monday morning, and others seemed sure to follow). Amid the musical chairs to make the playoffs, Minnesota’s Adrian Peterson came up just nine yards shy of his quest to overtake Eric Dickerson’s single-season rushing record of 2,105 yards. His 199 yards, however, helped the Vikings land a playoff berth. The Redskins also were carried to the playoffs by a running back, rookie Alfred Morris, a little-known sixth-round draft pick out of Florida Atlantic, who gained a team record 200 yards in Washington’s win-or-go-home 28-18 victory over Dallas. To test your knowledge of Week 17 NFL developments, take this 12-question quiz.