Penelope Cruz played the same character in 'Vanilla Sky' as she did in the Spanish version of the same film, 'Abre Los Ojos'.

At Tom Cruise's birthday party, when he is hugging everyone and they are wishing him a happy birthday, you can see Steven Spielberg walk up to him in a brown coat and a Pre-Crime baseball cap (from Minority Report) and say, "Happy birthday ya son of a b****," but in a friendly manner of course.

In the opening scene at David Ames' apartment as he is getting out of bed, a poster of the Bob Dylan album that he later recreates with Sofia is hanging on his bedroom wall.

When Tom and Penelope Cruz make the drawings of each other, she shows her caricature sketch of Tom. The drawing was done by James Malia (www.jamesmalia.com) who has done caricatures for Will & Grace and other stars/shows.

Cameron Crowe was originally going to give the title "Vanilla Sky" to his movie "Almost Famous", but for some reason he didn't. So he instead gave it to this movie, which was originally called "Open Your Eyes", after the Spanish version "Abre Los Ojos", which also starred Penelope Cruz. I think that title makes more sense, but they might have thought it was too similar to "Eyes Wide Shut" which also starred Tom Cruise.