The best cruise lines for themed cruises Sam Jamieson writes I'd like a cruise that makes good use of time at sea. I've heard that some have special activities or themes. Which lines offer these and what sort of interests can you pursue? Sara Macefield, cruise expert, writes Themed cruises have been a well-established part of the cruising mix for years, offering mainstream diversions such as photography, ballroom dancing and cookery. What has changed is the variety and scope of special interests that are now available. Today's passengers, for example, can become amateur sleuths on murder- mystery sailings, sing on musical voyages, or reach for the stars on astronomy-themed cruises. And for those who feel a little more daring, there are even nude cruises. This doesn't mean that the more mainstream diversions can no longer be found, they have simply moved on, spreading through the ocean-going cruise market and into river cruising, too. Cookery cruises, for example, have gone more upmarket and specialist: Silversea Cruises (0844 251 0837; silversea.com) offers courses by the Relais & Châteaux cooking school; P & O Cruises (0843 374 0111; pocruises.com) has sessions with celebrity chefs such as Marco Pierre White; while those offering wine appreciation courses with viticulturists and renowned wine experts include Celebrity Cruises (0844 493 2043; celebrity cruises.co.uk), AmaWaterways (0808 223 5009; amawaterways.co.uk) and Avalon (0800 668 1802; avaloncruises.co.uk). If you have a sweet tooth, Thomson Cruises" (0871 231 4691; thomson.co.uk) offers chocolate-making and tasting voyages in its "Live the Dream" workshops on its transatlantic crossings. Fred Olsen Cruise Lines (01473 746175; fredolsen cruises.com), meanwhile, has its own programme of special-interest voyages called Vistas, offering more than 15 topics, ranging from antiques and classical music to Nordic legends, while Saga Cruises (0800 096 0079; travel.saga.co.uk) offers a similar programme of themed sailings. Oceania Cruises (0845 505 1920; oceaniacruises.com) featured its first "Signature" cruises this year with voyages exploring subjects such as health and wellness, wine and food and music. And talking of music, you'll find musical interludes including jazz sailings on Crystal Cruises (020 7399 7601; crystalcruises.co.uk) and a 200-strong choir made up of passengers on a special National Symphony Orchestra sailing next September with Cunard (0843 374 2224; cunard.co.uk). Or you can dance, and not just ballroom either: P & O Cruises" Strictly Come Dancing sailings feature some of the show's stars. If you prefer walking, try one of the "Footloose" walking-themed sailings in the Scottish Highlands and islands with Hebridean Island Cruises (01756 704700; hebridean.co.uk). Hurtigruten (020 8846 2666; hurtigruten.co.uk), meanwhile, offers various nature-orientated itineraries along the Norwegian coastline. More novel options tend to be one-offs organised by travel companies chartering cruise ships and organising their own entertainment. For example, the American company Sixthman (001 877 749 8462; sixthman.net) specialises in "rock festivals at sea," while another American company called Whodunit Productions (001 661 297 3208; whodunit cruises.com) offers murder-mystery cruises; the Texan firm Bare Necessities (001 512 499 0405; cruisenude.com) is the company that offers those naked sailings (to the Caribbean). Finally, Adore Cruises (0800 954 1544; adorecruises.co.uk) has Elvis-themed cruise-and-stay holidays, combining a stay at Heartbreak Hotel in Memphis with a Caribbean cruise. A combination guaranteed to get Elvis fans all shook up. About Sara Macefield Sara is an award-wnning cruise writer, and a travel journalist for more than 20 years.