Before filming the scene with the car buried in the snow, Brittany Murphy and Ashton Kutcher had an argument, which helped them get through the scene without breaking into laughter.
It was an accident when Ashton Kutcher was hit by the "10 pound" ashtray by bouncing off a prop. He recovered but had a large goose egg for about a week.
While filming the scene with the cockroach, they lost it and had to shut down production for twenty minutes in order to find it.
When Tom and Sarah first arrive at their French hotel, they playfully trot up the stone path. This was improvised by Ashton Kutcher and Brittany Murphy during filming.