Like children on Christmas Eve, we might have trouble sleeping tonight knowing Iron Man 2 hits theaters tomorrow. Maybe we're so excited because it's been a while since we've seen a great action movie. Or maybe we just can't wait to see two of our favorite girls, Olivia Munn (who has a secret role) and Scarlett Johansson, on the silver screen. You see, Scarlett looks incredible in just about every movie she's ever been in, especially when it's time for some action. See for yourself with our collection of Scarlett Johansson's hottest roles...