On the new Norwegian Bliss, cruise passengers can drive go-karts on a two-story racetrack, listen to a Beatles cover band inside a replica of Liverpool's Cavern Club or play laser tag in a space-themed, outdoor arena.

Those are just three of the dozen or so entertainment options on the ship, which cost $1 billion to build and will ply Alaskan waters this summer and the Caribbean in the winter. Prices for a one-week Alaska trip in mid-July range from $2,800 per couple for an inside cabin to more than $11,000 for the company's exclusive Haven suites.

Gone are the days when entertainment at sea consisted of a lounge act near the mini casino and shuffleboard on the lido deck. As Norwegian Cruise Line Holdings Ltd., Carnival Corp. and Royal Caribbean Cruises Ltd. build ever larger vessels and try to lure younger guests, they're unleashing an arms race to deliver ever more-elaborate onboard activities.

Carnival's newest vessel, the 3,960-passenger Horizon, has a Dr. Seuss water park, a Havana-themed night club and an Imax theater. In March, Royal Caribbean christened the industry's largest ship, the 5,518-guest Symphony of the Seas, featuring an outdoor aquatics arena with acrobats, a zip line and wave machine for onboard surfing.

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