US President Barack Obama (R) walks on stage at the Aragon Ballroom in Chicago, Illinios, August 3, 2011, as Herbie Hancock (L), members of the band OkGo (C), Jennifer Hudson (3rd R) and Chicago Mayor Rahm Emanuel (2nd R) sing “happy birthday” to him. Obama turns fifty on August 4, 2011. AFP PHOTO/Jim WATSON (Photo credit should read JIM WATSON/AFP/Getty Images)