Get a double dose of hard rock at the Ozzy Osbourne and Rob Zombie concert on Saturday at the Verizon Center. Last year, Osbourne (above), a heavy-metal fixture whose career has spanned almost four decades, released his first album in six years with new studio material. Zombie, best known as the front man for the disbanded metal group White Zombie, has enjoyed a successful solo music and film career. The concert starts at 7:30 p.m. Tickets are $39.75-$89.75. The center is at 601 F St. N.W., Washington. Call 410-547-7328 or go to ticketmaster.com.