14. Joseph Gordon-Levitt As Neil - Mysterious Skin
When Joseph Gordon-Levitt auditioned for Mysterious Skin, he was coming off of nearly a decade of starring on 3rd Rock From the Sun and a few well-received but minor independent films. His audition is good in and of itself (after all, it got him the lead role in the film), but its larger significance has to do with his reinvention as an actor. It serves as a statement for what type of work Joseph Gordon-Levitt was interested in pursuing as an adult -- that is to say, risky, intriguing, and always surprising. For the most part, he's stuck to that, becoming one of the most engaging actors of his generation, and this audition shows that same intensity and purposefulness.
13. Marlon Brando As Jim - Rebel Without a Cause
Months before Marlon Brando performed the role of Stanley Kowalski in the Broadway production of Tennessee Williams' A Streetcar Named Desire that would make him a highly in-demand actor, Warner Brothers brought him out to Hollywood for a screen test. Then only 23 years old, he read with a very early draft of Rebel With a Cause, a film that the studio had purchased the rights to during the 1940s but wouldn't end up shooting until 1955. Although the script underwent major changes over the years, it's intriguing to think about what would have happened if Brando had starred in Rebel Without a Cause rather than James Dean, the iconic actor who made the lead character of Jim famous and jump-started the teenage revolution. Even in this very early footage, we can see his charisma, sensuality, and trademark lack of reverence for the movie industry.