Jennifer Aniston is back on the big screen in 'Horrible Bosses,' and we were with the former "Friends" star back when she was just 21 years old and starting out on TV!Before "Friends," Jennifer landed a plum part on the "Ferris Bueller" TV series in 1990, taking on Jennifer Grey’s role as Bueller's younger sister, Jeannie."I love the film," Jennifer told us in her first ET interview. "['Ferris Bueller's Day Off'] was one of those movies that you rent every week with your friends and watch every week, and know all the lines, and you know everything that happens next, and I loved it. It was a great movie." (ETonline.com)