Chris Brown was persona non grata in Las Vegas over the weekend. Because he isn’t yet 21, the singer was turned away from the Swagg bash at Tao Beach, where Jamie Foxx, Anna Paquin and Stephen Moyer, Busta Rhymes and Nelly partied. Brown was looking for a place to celebrate his 21st birthday, which is tomorrow, but hadn’t found any clubs that would welcome him and his posse. Brown later garbled the national anthem at the welterweight fight between Sugar Shane Mosley and Floyd Mayweather, drawing pans from fans, some of whom thought it was inappropriate for him to perform at a high-profile boxing match given his history of using his fists on his then-girlfriend Rihanna last year. Brown reacted to the criticism of his performance on Twitter, writing, “Im human. how many of u r perfect????????” He closed his evening with friends at the Sky Villa at the Palms Hotel.