Want to go on a clothing-optional crocheting cruise? There may be one out there.

Theme cruise ships have bikers, nudity and a whole lot more
If you have a passion, chances are you'll find a cruise tailored to it. Specialty or theme cruises cater to a wide variety of lifestyles, hobbies and interests: Yoga, fitness, cooking, Christian music, mystery, scrapbooking, baseball, golf and solar eclipse cruises abound.

And if you can't locate a theme cruise organized around your pastime, you can find someone who will put one together for you.

The theme could be anything from poker to Pilates to personal finance. As long as it's legal and other people share your interest, a travel agent can book a block of staterooms aboard a scheduled cruise and work with the cruise line to plan an itinerary suited to your group.

Except for special activities, such as workshops and lectures available only to theme-cruise participants, your group will be a part of a regular cruise, sailing and blending in with other passengers.

On a motorcycle cruise, you can explore exotic destinations without the hassle of shipping your bike or renting someone else's. Even if yours isn't a Harley, you can wheel your Suzuki, Ducati, Yamaha or whatever your ride (just no trikes!) aboard any of the cruises offered by Entertainment and Travel Alternatives (ETA), now in its seventh year of motorcycle cruises.

Starting in April, you can drive your bike right to the pier at Port Liberty in Bayonne, N.J., and sail away to the Caribbean with ETA on Royal Caribbean's Explorer of the Seas. There are varying itineraries that give the group priority disembarkation, private cocktail parties, and escorted and insured motorcycle excursions at various ports.

Sometimes special-interest groups will charter a ship, as is the case with an upcoming music cruise offered by Cayamo. The program, called "A Journey through Song," stars the Indigo Girls, Lyle Lovett, Patty Griffin, John Hiatt, Shawn Colvin, Brandi Carlile and a lineup of other artists who provide entertainment on this seven-day Eastern Caribbean itinerary aboard Norwegian Dawn.