A skeleton grabs a sword and slashes viciously at Sinbad. A 9-foot-tall Neanderthal man fights to the death with a saber-toothed tiger. All the while, the boys and girls in the fourth row forget about their popcorn and are hypnotized by the images on the screen. It's hard to believe so many years have passed since the last Sinbad movie held kids spellbound at Saturday matinees. The movies were …