We have run into several couples that have developed a schtick of signing onto cruises by doing lectures or teaching classes. We've found people doing watercolor classes, teaching languages, lecturing on piracy, teaching improvisational comedy, organizing passengers into chorale groups. It generally only works on long- like transatlantic/pacific cruises with lots of sea days. They get a cabin (on the crew decks) meals, and a stipend. What's better than a free cruise? Getting paid to take one!
Jim