Titanic: Why oh why is one of the people getting on the life boats wearing a digital
watch? Surely they weren't around in 1912? 

Austin Powers in Goldmember: Austin Powers left school in 1959. He would have been 18 then. This means that the family holiday in Belgium, when he was a baby, would have been in 1941. Continental Europe would have been an odd choice for a family holiday that year, what with World War II going on and everything.

American Pie: In the bedroom scene the girl is holding a clear cup full of beer. The camera goes off her and when it comes back she is holding a blue cup. The camera goes back off her then on her and the cup is clear again.

Signs:  I still can't get over how stupid the aliens are in this movie. If they are an advanced race that can travel through space, why are they naked and unarmed in their invasion? You'd think some weapons, armor or tools would help. You know, so if you get locked in a room so you aren't foiled by wooden doors and windows. Plus what interest did they have in the planet? The planet is 75% water which kills them, and it mentions something about "hunting humans" which implies eating people. Humans are also primarily constituted of water. They'd die if they tried.

Romeo And Juliet (1968): There is a high rise, modern building in the background during the opening fight.

Silence Of The Lambs: Jodie Foster has very blue eyes. When they flashback to her childhood, when she is crossing the lawn to greet her father, the girl playing the young Clarice has dark eyes

Silence Of The Lambs: At the end of the film, when Hannibal is telling Clarice about having "an old friend for dinner" a camera crew can is reflected in his sunglasses.

Hannibal:  When the Italian Police Inspector is on the pay phone in the middle of the street and he gets the recording that tells him how to go about collecting the reward money for Hannibal's "capture" there is a message at the end of the info that lets the caller know that they could press 1 for instructions in French, 2 for German, 3 for Italian, etc... However these instructions are in English! If you speak a different language you wouldn't understand it. And anyone who has ever called a machine like that will tell you that the instructions for each different language are in that language...

Phenomenon: After John T's passing the caption comes up 1 year later and they are celebrating his birthday. He was struck by lightning on his birthday and took three months to be diagnosed and die. The caption should say 9 months later.

Commando: One of the most blatant mistakes ever committed to film. The yellow Porsche is totally wrecked on the left side, until Arnie drives it away, and it's fine.