Cruise lines sometimes are able to negotiate special privileges for passengers. The Guggenheim museum in Bilbao, Spain, opened on a closed Monday for Radisson Seven Seas Voyagers' passengers.

Toss all cruise stereotypes overboard.

Ballroom-dancing seniors and booze cruises with wet T-shirt contests are both old news.

These days cruising can mean Cordon Bleu cooking classes with Radisson Seven Seas, getting down with your favorite bluegrass musicians on Carnival or chatting up your favorite author on the ‘‘Get Caught Reading at Sea’’ cruise.

The burgeoning cruise industry has had great success providing something to float everyone’s boat these days. Just look at the numbers: Cruise Lines International Association reports its members’ total annual passenger load of 9,107,000 in 2004 is more than double the number they carried a decade earlier. That reflects how inventive the industry has been - tapping into hobbies, lifestyles and the family travel trend.

Building on his annual wish to gather with family, Hank Marxen, 38, of San Diego, used a cruise both to create a mini family reunion and to satisfy his own bluegrass music sweet tooth.

Carnival Sensation’s bluegrass cruise got his parents out of North Dakota plus a few siblings and their spouses along for the sailing from Tampa to the Caymans, Cozumel and New Orleans. ‘‘A great one-time excursion for someone like me who likes more biking- and hiking-type vacations,’’ Marxen said.

Many cruises are well-suited to family travel, since families can gather for meals and some events and go their own way for others. The wildly popular Princess and Holland America cruises to Alaska attract family travel, partly because shore excursions offer experiences that range from dog-sledding to glacier-walking.

The good ships Disney make kids deliriously happy, too, though parents may feel a bit too Mickeyed with.

Though cruises are now appealing to all ages, higher-end cruise lines do cater mostly to the over-50 demographic. These are the people with money and time.

‘‘We like Radisson Seven Seas,’’ said Charles McCoy, 82, of Orinda, Calif., who has taken a dozen cruises. He and wife Joye, 77, like the fact that ‘‘you can be as private as you want to be,’’ said McCoy, who gets a suite so they can enjoy the balcony.. Radisson offers a full menu of shipboard life - bridge, bingo, expert lectures, exercise classes, golf lessons, tea parties - both on port days and at-sea days.

‘‘We do half the shore excursions,’’ said McCoy. ‘‘I’m a cheapskate.’’

The size of today’s ships has also changed cruising. There are tiny ships, such as those owned by Cruise West, that can prowl the shores of Alaska with dolphins swimming alongside. When someone’s binoculars spot a grizzly on shore, the ship can nose in for a closer look.

Then there are behemoth ships such as the Grand Princess, floating like a high-rise outside Venice, unloading 2,600ze ships with 104 suites, attracting people who want a yacht experience but may not own one (but probably could afford to). Masseuses magically appear on deck offering massages to reclining passengers. All cabins are suites and all have Wi-Fi access. Itineraries: all over the world, depending upon the season. 800-929-9391; www.seabourn.com.

Silversea Cruises has four small ships ranging from 292 to 382 berths. The ships go all over the planet and it’s a very popular line among those who can afford it, named No. 1 small-ship line by a reader survey in Conde Nast Traveler Magazine. 954-522-4477; www.silversea.com.

n Oceania Cruises has three 684-berth ships. Five-star menus are crafted by Jacques Pepin. Itineraries rove the world, including a stop in the newly opened port in Libya. 800-531-5658; www.OceaniaCruises.com.

-Sailor at heart

Billowing sails are beautiful, and a couple of cruise lines combine real sails with motor-driven ships.

Windstar Cruises has two ships that sail the Caribbean, Costa Rica, Mayan Riviera, Panama Canal and Mediterranean, plus a trans-Atlantic crossing for serious sailors. 800-258-7245; www.windstarcruises.com.

Maine Windjammer Association is an informal group of commercial schooners that offer multiday sails. Most of these ships are restored historic ships. 800-807-9463; www.sailmainecoast.com.

-More sailing

Other kinds of cruises that are very popular are European and American riverboat cruises.

Peter Deilmann is popular for cruising European waterways. 800-348-8287; www.deilmann-cruises.com.

And if low, low budget is on your mind, check out new easycruise’s bare bones European ships attracting the under-35 crowd with low prices and a hop-on, hop-off program - no need to book the entire cruise; just a few ports will get you onboard. Book on www.easycruise.com.

Delta Queen Steamboat Company, sails on the Mississippi River. 800-543-1949; www.deltaqueen.com. Because of Hurricane Katrina, New Orleans has been removed from itineraries. But no cruises have been canceled.