The cruise business is expanding through a strange—and sometimes shocking—array of themed voyages. Don't forget your Pepto

ANNOYING:History ChannelExperts lecture on the Civil War, World War II, and Caribbean history. From $2,074, seven nightsAmerican GirlDolls get their own teacup at dinner. There's even a doll hair salon. $3,313, seven nightsNational ReviewThe right-wing journal launched its maiden voyage in 1994. $1,899, seven nightsVH1This year the "Best Cruise Ever" featured concerts by Train, Lifehouse, and Colbie Caillat. $799, four nightsA.C. MilanCruising with soccer players isn't the only draw: Coaches teach clinics and organize matches. $1,501, seven nightsThe Biggest LoserLose pounds alongside former show contestants. Experts also advise on nutrition and fitness. $1,295, seven nightsALARMING:Richard SimmonsSweat with the fitness legend on his "Cruise to Lose." $1,245, seven nightsMacsThe 11th MacMania trip offered seminars on apps and social media. $1,888, seven nightsAmerican Conservative UnionGet chummy with Rummy. $1,630, seven nightsBackstreet BoysThe ship docks in Nassau for a private beach party and BSB concert. $699, three nightsStar TrekPast Cruise Trek cruisers have been joined by motley cast members. $899, seven nightsPrairie Home CompanionGarrison Keillor's cruise is already full. $1,900, seven nightsAPOCALYPTIC:Little House on the PrairieFans can sail with the cast—sans the late Michael Landon. $879, seven nightsTwilightFans were disappointed to learn the second annual cruise was canceled. $1,049, seven nightsKid RockGetting wasted was the main form of entertainment on the Detroit rock renegade's April sea adventure. $899, four nightsBook of MormonCruisers explore ports with significance to the religious text. $559, seven nightsYoung American FoundationCruise with Karl Rove—for a hefty fee. $7,800, eleven nightsTitanicYes, a cruise honors the sunken ship. $1,490, twelve nights