Not to say it wouldn't be the contemporary classic that it is today, but 'The Matrix' would've taken us down a whole different rabbit hole had Will Smith not passed on the role of Neo, opening the door for Keanu Reeves to don the dark trench coat. Can anyone really imagine The Fresh Prince uttering lines like "Whoa, déjà vu" with the same sense of stunned bewilderment?

How about if Ralph Macchio went time-traveling as Marty McFly, or Tom Cruise danced his heart out as Ren McCormack?

Rarely does a project in Hollywood start and finish with the same lead actors attached. Just see this summer's thriller 'Salt,' where the role of Angelina Jolie's wrongly accused spy Evelyn Salt was originally to be played by Cruise (as EDWIN Salt, natch).

We thought it'd be amusing to give these 15 casting fun facts -- actors (reportedly) originally attached or offered the roles you see below -- some visual representation.