Continuity mistake: In the scene where Matthew Broderick leaves his wife's hospital room and has to sniff out which book she picked off the shelf while he is gone, you can see that she picked a green book. But when he comes back in he takes a blue book off the shelf, as she says that that was the correct one.
Richard Feynman: Mathematics is a language. It's very difficult. It's subtle. You couldn't say those things any other way - and I can talk to dead people with it. I talk to Copernicus every day.