Today, Jennifer Aniston turns 50. We salute the actress by recalling some her finest achievements and delving into the fitness routines that keep her so fit and youthful On Saturday night Jennifer Aniston celebrated her 50th birthday bash in her Los Angeles home. The major event included some of the biggest A-listers in Hollywood – gal pals Gwyneth Paltrow, Reese Witherspoon and Kate Hudson. Others included Katy Perry and boyfriend Orlando Bloom, Lisa Kudrow, Leonardo DiCaprio, Robert Downey Jr, even…