'Indiana Jones and the Kingdom of the Crystal Skull' co-stars HARRISON FORD , KAREN ALLEN and SHIA LaBEOUF hit the streets of New York for a special fan screening of their highly anticipated adventure, in theaters Thursday -- and ET was there! Harrison came holding hands with girlfriend CALISTA FLOCKHART , who has been jet-setting around the globe with her man for the film's kick-off festivities. And his advice for young Shia? Be humble! "There's no trick to being humble," Harrison ...