R you going my way? Rapper Jay-Z had subway riders gawking in New York on Saturday as he took the R train from Manhattan to Brooklyn for the last of eight shows at the new Barclays Center. If the stadium takes off, it deserves to be known as the House that H.O.V.A. built. The Brooklyn born-and-bred hip-hop prince arrived for his concert via public transportation escorted by police and other security personnel, and waiting fans swooned for the man who has become the public face for the new home of the Nets, even though he owns only one-fifteenth of one percent of the team.