Roughly 35 million people take a cruise ship holiday every year and spend upwards of $60 billion dollars. Maybe it's the appeal of only having to unpack your suitcase once, or the idea that you travel from destination to destination while you sleep, maximizing your precious vacation time. But yes, cruising can be fun. Of course, there are the occasional accidents, illnesses, crimes and mysteries-with that many people onboard in somewhat cramped quarters, how could there not be? Also, being out on the open ocean has its inherent risks. But for those who don't care to fly or who have their grandmothers in tow, cruises are a solid, family friendly option, as long as you follow a few simple rules.