UFC star Georges “Rush” St-Pierre, one of the most popular and successful athletes in mixed martial arts, will meet fans and sign autographs at The Sports Authority store at 636 Avenue of the Americas (at 19th St.) in Manhattan on Thursday beginning at 6 p.m. St-Pierre, the current UFC welterweight champion, is a native of Quebec. He occasionally trains at Renzo Gracie Jiu-Jitsu on 3oth Street.