Fox's decision to release the remake of "The Omen" on 06-06-06 was a nifty little gimmick which netted the movie a ton of press. Opening a movie on a Tuesday might have shaken a few customers loose too, but it's really all about the DVD sales, and any press is golden.
It's so different from the old days when local movie houses did their own stunts. Back in Scotland in the early days some cinema owners would set up a camera in some public place, then just shoot a few reels of film. There was always a sign by the camera declaring the film would be shown on a particular date at the movie house. People would turn up in droves to see themselves on screen.
My grandfather used to run stunts at his theaters regularly. When James Whale's "The Invisible Man" hit Glasgow in the early 1930's one manager announced the Invisible Man was visiting the theater that evening.
He offered a reward of a few shillings to the patron who found the guest of honor and brought him to the managers office. Apparently the place went wild as people spilled out into the lobby and the alleys around the building looking through the trash cans for their prize.