Even if you've spent most of your cruise basking in the Mexican sun or eating your way through the Mediterranean, your vacation can feed more than your need to just relax and unwind.
Thanks to guest speakers, you can learn about topics as diverse as reality and scripted TV shows and South American politics. No matter the line, you'll find academics, politicians, scientists, musicians, artists, accomplished chefs and TV celebs.
Sometimes they are part of lecture series or charter programs; other times, they are one-offs. Those lectures that enhance the destination are even better.
Here are some of the most intriguing options this year:
Jeff Greenberg, casting director
May 25, Panama Canal: 18-day sailing from Los Angeles to New York City
Crystal Cruises' Crystal Symphony
The Emmy-winning Greenberg, who has worked on "Modern Family," "Frasier" and "Cheers," will discuss his experiences in Hollywood.
There are other nods to the entertainment industry on this sailing out of Los Angeles, including a lecture by Jim Jimirro, founding president of Disney Channel, and a digital filmmaking course.
The ship also has Silk Road, a Japanese restaurant helmed by Nobu Matsuhisa, and Prego, an Italian restaurant designed by Piero Selvaggio of Santa Monica's Valentino.
"The Deadliest Catch" cast
Seven-day sailings round-trip from Vancouver to Anchorage
Princess Cruises' Pacific Princess and Ruby Princess
Princess Cruises has partnered with Discovery Communications to bring aboard Capt. David Lethin and the rest of the crew from the Aleutian Ballad from the reality show "The Deadliest Catch." These are true fisherman, not actors; they will tell stories of their experiences crab fishing.
Guests can also learn about logging from a lumberjack, try their hand at ax-throwing, and order local seafood in the dining room and specialty restaurants that serve the signature dishes of Alaska. Lethin and his crew will be on select sailings on Ruby Princess and Pacific Princess throughout the summer.
Lech Walesa, former president of Poland
June 4, Baltic, 10-day sailing from Copenhagen to Stockholm
Ponant's Le Boreal
This visit from the Nobel Peace Prize winner, organized by Smithsonian Journeys, takes place in Gdansk, Poland, after a day spent touring the historic Lenin Shipyard and the Monument to the Fallen Shipyard Workers.
The lecture will feel intimate, thanks to the size of this luxury ship (120 staterooms).
Glenn Kranking, an expert on Scandinavia and the Baltic, will also speak on the Vikings and Nordic explorers of the region.
Cesar Gaviria, former president of Colombia
Sept. 27, Latin America
14-day sailing from Panama City to Lima, Peru
National Geographic Expeditions' National Geographic Explorer
This expedition-style cruise sails to lesser visited ports along the Pacific coastline from Panama to Colombia, Ecuador and Peru. Gaviria will join this sailing to discuss democracy in the region.
The ship sails through the Panama Canal and then the trip focuses on the history, from the conquistadors to the present day, and the wildlife of the region, including butterflies, spider monkeys and jaguars.