Carnival offers round-the-clock excitement on its "Fun Ships," which are like floating resorts. There's so much variety that you can be as high-spirited or as low-key as you want. You'll find dozens of activities, top-notch Vegas-style revues and a variety of nightspots, from high-energy discos to cozy piano bars. Carnival ships boast some of the largest showrooms and best entertainment at sea, and their lively casinos provide hours of fast-paced action.