Jay-Z and Beyoncé spent their Fourth of July overseas in London, where Hov headlined Day 3 of the Barclaycard Wireless Festival in Hyde Park. Hip-hop’s first couple is among Forbes magazine’s top 20 richest and most powerful celebrities. Mr. Carter landed at No. 15 with $63 million, while the Mrs. came in second behind Oprah Winfrey, raking in $87 million in the past year.