There is a HUGE variety of theme cruises available. In fact you could say the current "theme" in the cruise industry is to theme cruises
There are theme cruises covering just about every musical gendre.. jazz cruises, country artist cruises, rock cruises, big band, classical, etc.
There are cruises built around political pundits, vamp cruises, cougar cruises, goth cruises, nude cruises, golf cruises, celebrity cruises, soap star cruises. The list is truly almost endless of different affinity groups putting together cruises.