Artist Jeff Koons turns 55 today. Cindi Leive, the editor-in-chief of Glamour, is turning 43. Opera great Placido Domingo is 69. Reclusive Microsoft co-founder Paul Allen is turning 57. U.S. Attorney General Eric Holder is 59. Federal judge Kimba Wood is turning 66. Geena Davis is 54. Film heavyweight Mike Medavoy is turning 69. Singer-songwriter Chan Marshall turns 38. Singer Billy Ocean is 60. And golf legend Jack Nicklaus celebrates his 70th birthday today.