Movies show us things that have already happened before the camera eye, so memory - which does the same thing in the mind's eye - is a subject they're well suited to. Hence all the flashbacks and nostalgia scenes in countless Hollywood pictures.
Sometimes the theme is handled in a clever way, as in "Memento," or a flashy way, as in "Total Recall," or a witty way, as the coming "Eternal Sunshine of the Spotless Mind" promises to do.
And sometimes it shouldn't be handled at all. "50 First Dates" turns a good premise into a romantic comedy that's vulgar, sentimental, and as dumb as the sea creatures the veterinarian hero cares for in a Hawaii aquarium.
Adam Sandler plays Henry, a womanizer who'll tell any lie to win a woman's attention. Then he meets Lucy (Drew Barrymore), who seems to like him - but reacts the opposite way the next time he talks to her.
It turns out brain damage has destroyed her short-term memory, so she only remembers life up until the accident that injured her. Everything more recent is erased while she sleeps at night, including her encounters with Henry, who can't get her out of his thoughts. Each day he woos her again, and each time it's a whole new start.
Meanwhile her father and brother keep her from realizing her problem by pretending it's always the same day in October. The same basketball game is on TV, and it's always her dad's birthday.
The movie's few amusing moments are less like "Memento" than "Groundhog Day," as Lucy's family uses her gift to her dad - a video of "The Sixth Sense," with a surprise ending that never fails to surprise her - for the umpteenth time.
There's good potential in the film's idea of a woman who can't strike up a real romance for reasons she can't control, and a man who loves her so much he'll try anything to help her. But it's hard to enjoy this when you're barraged by bathroom humor, animal stunts, and gags about a character whose memory loss is so bad he's called Ten-Second Tom.
One first date is too much for this movie. Take my advice and forget it.
• Rated PG-13; contains sensuality and drugs.