For at least a decade, upscale resorts like the tony Treasure Beach in Barbados and all three Grand Lido resorts in Jamaica have lured adults with their guaranteed child-free vacations sans dirty diapers, spitball fights and other allegedly cute kid antics. Now the cruise-ship industry is following suit. Celebrity Cruises has just unveiled its line of all-adult trips to the Caribbean, Alaska and Hawaii. Dubbed Celebrity Escapes, these seven-or 11-night voyages offer grownup stage and comedy acts, wine tastings, salsa lessons and extended pool and spa hours. Prices for the Nov. 17 sailing start at $450--and next year that will jump to $950. But singletons, beware: more than 70% of those on Celebrity Escapes' first voyage two months ago were couples. If you want the seaside singles scene, stick to the Club Med in Cancun.