Celebrity birthdays for the week of Jan. 21-27: Jan. 21: Opera singer Placido Domingo is 83. Actor Jill Eikenberry is 77. Guitarist Jim Ibbotson (The Nitty Gritty Dirt Band) is 77. Singer-songwriter Billy Ocean is 74. Actor Robby Benson is 68. Actor Geena Davis is 68. Actor Charlotte...