It has been a long time since the hockey world's focus zeroed in on the Garden, maybe not since Wayne Gretzky's Great Goodbye on April 13, 1999. But that's where the sport's spotlight will be aimed tonight, when the Rangers and Penguins meet in a showdown that will feature a playoff atmosphere and the return of the world's most celebrated hockey player. The Rangers have the best record in the conference. The Penguins, with a nine-game winning streak, are second-best by six points with a game in hand at the top of the homestretch, but that's the secondary storyline to Sidney Crosby's dramatic return, as far as everyone who doesn't have blueblood running through his or her veins is concerned.