This isn't an easy time for Dan Loeb. (The billionaire hedge funder was forced to start renting his Gulfstream jet by the hour recently.) But hopefully he'll get a chance to enjoy the big day: He turns 47 today. Others celebrating: Katie Holmes is turning 30. Brad Pitt is 45. Steven Spielberg is 62. Christina Aguilera is turning 28. PR guru/filmmaker Dan Klores is 59. Randi Weingarten is 51. Memorial Sloan-Kettering chief (and Nobel Prize winner) Harold Varmus is turning 69. Keith Richards is turning 65. Model agency owner Faith Kates is turning 51. Ray Liotta is 54. Former Miss USA Tara Conner is 23. And troublemaking rapper DMX is turning 38.