I saw Open Water the other night. It is based on the a 1998 case where a dive boat left a couple on the Great Barrier Reef. It is similar to the Blair Witch Project. The actors are unknowns, there are no special effects (all sharks are real) and the focus is on realism. The protoganists are trying to repair their relationship with a vacation when they get left behind. So we gets lots of bickering, which is realistic, but may bore some people. I found the movie quite unsettling and frightening, but then again, I like to snorkel and I am wary of sharks. Others may be less interested. I find this style of horror to be much more interesting than the gore fests that are topping the charts. Shark attacks are of course uncommon. Check the International Shark Attack File to find out where the attacks happen and how to reduce your risk of being gobbled up by a shark.